IMItUHHJIM 


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BIOLOGY 
LIBRARY 

G 


MANUAL  OF 

BACTERIOLOGY 
AND   PATHOLOGY 

FOR  NURSES 


BY 

JAY  G.  ROBERTS,  Ph.G.,  M.D. 

OSKALOOSA,    IOWA 


ILLUSTRATED 


PHILADELPHIA  AND  LONDON 

W.  B.  SAUNDERS   COMPANY 
1914 


BIOLOGY 

LIBRARY 

G 


Published  August,  1912.     Reprinted  November,  1912,  and  January, 


Copyright,  1912,  by  W.  B.  Saunders  Company 


Reprinted  June,  1914 


PRINTED    IN    AMERICA 

PRE88   OF 

W.    B.    SAUNDERS    COMPANY 
PHILADELPHIA 


TO  MY  MOTHER 

THIS  BOOK  IS  AFFECTIONATELY 

DEDICATED 


PREFACE 

THIS  work  is  the  result  of  several  years  experience  in 
teaching  the  subjects  of  bacteriology  and  pathology  to 
nurses.  It  was  early  discovered  that  there  did  not  exist 
any  work  on  these  subjects  which  seemed  adapted  to  the 
peculiar  requirements  of  the  busy  nurse  in  training  or  in 
practice.  The  fact  that  such  a  work  must  of  necessity  be 
brief  has  been  recognized,  but  a  constant  effort  has  been 
maintained  to  avoid  sacrificing  accuracy  or  lucidity  for 
brevity.  Considerable  space  has  been  devoted  to  the 
subjects  of  infection  and  immunity  and  to  bacterial  and 
serum  therapy,  because  it  was  realized  that  the  trained 
nurse,  because  of  her  intimate  and  continued  association 
with  them,  is  to  become  the  great  teacher  of  the  masses 
in  the  newer  developments  in  medicine  and  sanitation,  as 
the  physician  can  never  be,  and  she  should,  therefore, 
keep  abreast  of  the  times  on  these  subjects. 

The  subjects  of  microscopic  diagnosis  and  pathologic 
technic  have  not  been  entered  into  to  any  extent,  as  they 
are  of  interest  only  to  those  nurses  who  contemplate  be- 


4  PREFACE 

coming  surgical  or  bacteriologic  assistants,  and  such  are 
referred  to  the  more  pretentious  works  for  physicians. 

Physicians  returning  from  abroad  almost  universally 
remark  upon  the  superiority  of  the  nursing  in  most 
American  hospitals.  If  this  be  true,  and,  as  is  generally 
believed,  it  be  due  to  the  greater  amount  of  time  and 
attention  devoted  to  the  training-schools  for  nurses  by 
American  physicians,  it  is  the  earnest  hope  of  the  author 
that  this  little  book  may  aid  in  some  small  measure  in 
maintaining  this  enviable  position  of  the  American 
trained  nurse. 

In  conclusion,  I  wish  to  thank  the  students  of  the 
Oskaloosa  Training  School  for  Nurses  for  the  encourage- 
ment which  their  appreciation  of  the  lectures  upon  which 
this  book  is  based  has  given  me,  and,  finally,  to  express 
my  deep  obligation  to  my  wife,  who  has  aided  and  en- 
couraged me  in  many,  many  ways  in  the  preparation 
of  this  work,  especially  in  revising  and  transcribing  the 
manuscripts  and  in  correcting  the  proof  sheets. 

J.  G.  R. 

OSKALOOSA,  IOWA, 


CONTENTS 


BACTERIOLOGY 

PAGE 

INTRODUCTION  ...  1 1 


CHAPTER  I 

DEFINITION,  MORPHOLOGY,  AND  PHYSIOLOGY 16 

Bacteria 16 

Flagella 16 

Reproduction 17 

Fission 17 

Sporulation 17 

CHAPTER  II 

CONDITIONS  FOR  GROWTH  AND  PRODUCTS  OF  THE  GROWTH  OF 

BACTERIA 19 

Soil 19 

Saprophytes 19 

Stains 20 

Temperature 20 

Moisture 20 

Food 21 

Oxygen 21 

Light 21 

Products  of  Bacteria 21 

Protozoa 23 

CHAPTER  III 

INFECTION,  SUSCEPTIBILITY,  AND  IMMUNITY 24 

Infection 24 

Susceptibility 24 

5 


6  CONTENTS 

PAGE 

Immunity 24 

Bacteriolysis 25 

Agglutinins 26 

Phagocytosis 26 

Aggressins 26 

Opsonins 26 

Bacterial  Vaccines 27 

Antitoxin 27 

Theories  of  Immunity 28 

CHAPTER  IV 

EXAMINATION  OP  BACTERIA,  MICROSCOPIC  DIAGNOSIS,  ETC 29 

CHAPTER  V 

BACTERIA  IN  DISEASE 32 

Koch's  Rules 32 

Infectious  Diseases 33 

Contagious  Diseases 33 

Avenues  of  Infection 33 

Period  of  Incubation 34 

Sources  of  Infection 34 

CHAPTER  VI 

PYOGENIC  BACTERIA,  PYEMIA,  SAPREMIA,  SEPTICEMIA,  INFECTIOUS 

DISEASES 37 

Pyogenic  Bacteria 37 

Septicemia  or  Septic  Infection 38 

CHAPTER  VII 

PATHOGENIC  BACTERIA  AND  DISEASES  CAUSED  BY  THEM 41 

Micrococci 4* 

Bacilli 44 

CHAPTER  Vin 

PATHOGENIC  BACTERIA  AND  DISEASES  CAUSED  BY  THEM  (Con- 
tinued)    Si 

Bacilli  (Continued) Si 

Spirilla 55 


CONTENTS  7 

CHAPTER  IX  PAGE 

PROTOZOA  AND  DISEASES  CAUSED  BY  PROTOZOA 58 

CHAPTER  X 

ANTISEPTICS,  DISINFECTANTS,  AND  GERMICIDES 60 

Disinfectants  and  Antiseptics 61 

CHAPTER  XI 

SUSCEPTIBILITY  AND  INFECTION 68 

Transmission  of  Infection 72 

Prevention  of  Infection 73 

General  Precautions  for  Nurses 73 

Special  Precautions:  Disinfection  and  Fumigation 75 

CHAPTER  XII 

IMMUNITY 80 

The  Causes  and  Mechanism  of  Immunity 81 

Acquired  Immunity 81 

Inherited  Immunity 85 

Methods  of  Producing  Active  Acquired  Immunity 85 

CHAPTER  XIII 

SERUM  THERAPY  AND  VACCINE  THERAPY,  ANTITOXINS,  SERUMS, 

AND  VACCINES 88 

Serum  Therapy 88 

Antitoxin 89 

Vaccine  or  Opsonic  Therapy 100 

Bacteriovaccines 103 

CHAPTER  XIV 

SERUM  DIAGNOSIS 115 

The  Tuberculin  Test 115 

The  Widal  Test  for  Typhoid  Fever 118 

Typhoid  Ophthalmoreaction 119 

The  Wassermann  Test  for  Syphilis 120 

CHAPTER  XV 

ANAPHYLAXIS 123 


8  CONTENTS 

PATHOLOGY 

CHAPTER  XVI  PAGE 

ETIOLOGY  OF  DISEASE 126 

Traumatism 126 

Heat 126 

Cold 127 

Insufficient  Air » .  128 

Poisons 128 

CHAPTER  XVII 

DISORDERS  OF  NUTRITION  AND  METABOLISM 130 

Foods 130 

Glycosuria  and  Diabetes 131 

Fever 132 

CHAPTER  XVIII 

DISTURBANCES  OF  CIRCULATION 134 

Hypostatic  Congestion 134 

Local  Hyperemia 134 

Passive  Hyperemia 134 

Local  Anemia 135 

Hemorrhage 135 

Embolism 136 

Infarct 137 

Thrombosis 137 

Edema  or  Dropsy 138 

CHAPTER  XIX 

RETROGRADE  PROCESSES 139 

Atrophy 139 

Degeneration 139 

Necrosis 140 

Gangrene 141 

CHAPTER  XX 

INFLAMMATION  AND  PROCESSES  OF  REPAIR 142 

Inflammation 142 

Degenerative  Changes 143 

Wound  Repair;  Regeneration 145 

Progressive  Processes 145 


CONTENTS  9 

CHAPTER  XXI 

PAGE 

TUMORS 147 

Connective-tissue  Tumors 148 

Teratoma  and  Teratoid  Tumors 155 


CHAPTER  XXII 

PARASITES  AND  DISEASE  (VEGETABLE  PARASITES) 156 

Diseases  Due  to  Bacteria 157 

Suppurative  Diseases  (Furunculosis,  Abscess,  Osteomye- 
litis, Otitis  Media,  Mastoiditis,  Etc.) 157 

Gonorrhea 158 

Lobar  Pneumonia 158 

Diphtheria 160 

Cerebrospinal  Fever 162 

Typhoid  Fever 164 

Asiatic  Cholera 166 

Tuberculosis 167 

Leprosy 170 

Plague 171 

Tetanus ." 173 

Glanders 175 

Anthrax 176 

Actinomycosis „ 177 

Influenza 178 

Syphilis 179 

Relapsing  Fever 181 

Malta  Fever 183 


CHAPTER  XXIII 

DISEASES  WHOSE  MICROBIC  CAUSE  HAS  NOT  BEEN  ISOLATED.  . .  184 

Hydrophobia 184 

Yellow  Fever 185 

Measles 186 

Scarlet  Fever 187 

Parotitis  (Mumps) 188 

Pertussis  (Whooping-cough) , 188 

Typhus  Fever 189 


10  CONTENTS 

CHAPTER  XXIV 

PAGE 

DISEASES  DUE  TO  ANIMAL  PARASITES 190 

Diseases  Due  to  Protozoa 190 

Amebic  Dysentery 190 

Trypanosomiasis  (Sleeping-sickness) 191 

Malarial  Fever  (Ague) 191 

Diseases  Caused  by  Cestodes 193 

Tapeworms 193 

Echinococcus  Disease 194 

Diseases  Caused  by  Nematodes  or  Round-worms 195 

Ascaris  Lumbricoides 195 

Oxyuris  Vermicularis 195 

Trichina  Spiralis 196 

Ankylostoma  Duodenale  (Hook-worm) 196 

Filaria  Sanguinis  Hominis 196 


INDEX 199 


BACTERIOLOGY  AND  PATHOLOGY 
FOR  NURSES 


BACTERIOLOGY 


INTRODUCTION 

THE  story  of  the  development  of  the  science  of  bac- 
teriology reads  like  a  romance.  For  untold  ages  man 
struggled  blindly  and  desperately  with  an  unseen  foe. 
Struggled  helplessly  and  afraid,  because  of  the  nature 
of  this  dread  adversary  he  knew  nothing;  he  could 
neither  see,  hear,  nor  feel  it;  it  came  and  went  like  a 
specter  in  the  night,  and  man  knew  it  only  by  the  havoc 
it  wrought,  and  he  measured  its  power  by  the  dead 
bodies  of  its  victims.  Wild  beasts  and  poisonous 
snakes  he  had  conquered;  heat  and  cold,  storm  and  calm, 
mountains'  heights  and  oceans'  depths  he  had  learned 
to  circumvent,  or  had  made  to  minister  to  his  needs; 
but  still  this  silent,  invisible  foe  stalked  up  and  down  the 
face  of  the  earth  exacting  its  grim  toll  of  life  and  health. 

Groping  blindly,  man  learned  some  things  about  this 
unseen  enemy.  He  learned  that  it  sometimes  infested 
the  food  that  he  ate  or  the  water  that  he  drank,  but  he 

11 


12  BACTERIOLOGY 

knew  not  how  nor  when.  He  learned  that  those  who 
were  seized  upon  by  this  foe  were  a  source  of  danger 
to  others,  as  were  likewise  their  clothing  and  their 
houses.  In  other  words,  he  learned  that  diseases  were 
contagious,  but  how  or  why  he  knew  not. 

For  ages  the  leper  had  been  considered  "  unclean/' 
and  since  the  dawn  of  the  world  of  man  had  plague- 
infested  cities  been  shunned,  and,  later,  those  who  were 
afflicted  and  their  habitations  were  purified  by  baths 
and  smudges  and  noxious  fumes. 

Then  an  observing  Dutchman  of  an  inventive  turn, 
Leeuwenhoek,  of  Delft,  about  the  year  1680  produced 
a  lens  of  such  power  that  this  enemy  of  man  could  be 
seen,  though  it  was  not  recognized  as  such  at  that  time. 
Though  Leeuwenhoek  certainly  discovered  the  existence 
of  bacteria  and  described  them,  neither  he  nor  any  one 
else  succeeded  in  connecting  them  with  disease  for  nearly 
two  centuries.  So  for  two  hundred  years,  though  its 
presence  was  known  and  its  guilt  ofttimes  suspected, 
the  disease  germ  remained  unconvicted. 

Oliver  Wendell  Holmes,  an  American  physician- 
author,  in  1843  suspected  the  cause  of  puerperal  fever 
and  wrote  on  its  contagiousness.  In  reply  to  the 
criticism  and  invectives  which  were  heaped  upon  him 
because  he  ventured  so  new  and  astonishing  an  idea  in 
medicine  he  wrote: 

"  It  is  as  a  lesson  rather  than  a  reproach  that  I  call 
up  the  memory  of  these  irreparable  errors  and  wrongs; 


INTRODUCTION  13 

no  tongue  can  tell  the  heart-breaking  calamity  they  have 
caused;  they  have  closed  the  eyes  just  opened  upon  a 
new  world  of  love  and  happiness;  they  have  bowed  the 
strength  of  manhood  into  dust;  they  have  cast  the  help- 
lessness of  infancy  into  strangers'  arms  or  bequeathed 
it,  with  less  cruelty,  the  death  of  its  dying  parent. 
There  is  no  tone  deep  enough  for  regret  and  no  voice 
loud  enough  for  warning.  The  woman  about  to  become 
a  mother  or  with  her  newborn  infant  on  her  bosom  should 
be  the  object  of  trembling  care  and  sympathy  wherever 
she  bears  her  tender  burden  or  stretches  her  aching 
limbs.  The  very  outcast  upon  the  streets  has  pity  upon 
her  sister  in  degradation  when  the  seal  of  promised 
maternity  is  Impressed  upon  her.  The  remorseless 
vengeance  of  the  law,  brought  down  upon  its  victim  by 
a  machinery  as  sure  as  destiny,  is  arrested  in  its  fall  by 
a  word  which  reveals  her  transient  claim  for  mercy. 
The  solemn  prayer  of  the  liturgy  singles  out  her  sorrows 
from  the  multiplied  trials  of  life,  to  plead  for  her  in  the 
hour  of  peril.  God  forbid  that  any  member  of  the 
profession  to  which  she  trusts  her  life,  doubly  precious 
at  that  eventful  period,  should  hazard  it  negligently, 
unadvisedly,  or  selfishly." 

In  1847  Semmelweis,  of  Vienna,  forged  a  link  in  the 
chain  of  evidence  which  was  at  last  to  demonstrate  the 
identity  of  this  unknown  foe  and  give  man  a  fighting 
chance  for  life.  Semmelweis  noted  a  high  rate  of  mor- 
tality for  puerperal  fever  in  a  hospital  ward,  the  attend- 


14  BACTERIOLOGY 

ants  of  which  were  in  the  habit  of  coming  direct  from  the 
dissecting  room  to  the  care  of  patients  in  confinement. 

Observing  the  similarity  between  puerperal  fever 
and  a  case  of  pyemia  caused  by  a  dissection  wound,  he 
suspected  their  identity,  and  the  dissection  room  as 
their  origin.  He  introduced  a  rule  providing  that  all 
attendants  from  the  dissection  room  must  cleanse  their 
hands  with  soap  and  water  and  chlorin  solution,  to 
"kill"  the  suspected  poison,  before  they  were  allowed  to 
attend  the  confinement  cases.  The  results  were  imme- 
diate and  astonishing.  The  cases  of  puerperal  fever 
were  far  below  the  average  for  that  period  among  cleanly 
midwives  and  attendants. 

But  it  was  in  the  study  of  fermentation  that  the  con- 
nection of  bacteria  with  disease  was  finally  demon- 
strated. Pasteur,  working  with  fermentation,  discov- 
ered its  bacterial  origin,  and  in  1869  demonstrated  that 
a  disease  of  silk- worms  was  due  to  bacteria.  Lister, 
in  1867,  concluded  that  suppuration  in  wounds  was  a 
form  of  fermentation  and  could  be  prevented  as  could 
fermentation.  His  results  from  the  application  of  asep- 
tic and  antiseptic  methods  in  surgery,  which  methods 
he  originated,  supported  his  conclusions,  and  he  is  known 
to-day  as  the  "Father  of  modern  aseptic  surgejy." 
Davaine,  in  1863,  produced  anthrax  in  animals  by  in- 
jecting them  with  blood  containing  anthrax  bacilli 
from  animals  having  the  disease.  This,  however,  did 
not  prove  the  bacillus  to  be  the  cause,  as  there  might 


INTRODUCTION  1$ 

be  other  substances  in  the  blood  which  caused  the 
disease. 

In  the  late  seventies  Pasteur  and  his  pupils  reproduced 
anthrax  in  animals  from  a  pure  culture  of  anthrax 
bacilli  grown  outside  the  body  of  an  animal,  thus  con- 
firming Davaine's  observations  and  settling  the  question 
of  the  cause  of  anthrax.  Koch,  in  1882,  discovered  the 
tubercle  bacillus  and  proved  it  to  be  the  cause  of  tuber- 
culosis. 

Jenner,  a  hundred  years  before,  had  produced  im- 
munity to  small-pox  by  inoculating  with  a  modified 
form  of  the  disease  cow-pox;  and  Pasteur,  now  working 
along  similar  lines,  produced  immunity  to  anthrax  by 
inoculating  animals  with  a  culture  of  the  germ  which  had 
been  attenuated  by  heating.  Behring,  in  1893,  Pro" 
duced  diphtheria  antitoxin,  and  the  beginning  of  the  end 
of  the  conflict  of  the  ages  was  apparent.  Flexner  has 
produced  a  curative  serum  of  great  value  in  cerebro- 
spinal  meningitis,  and  vaccination  against  typhoid  fever 
is  proving  very  valuable  in  the  armies  of  the  world. 
In  view  of  the  progress  made  in  the  establishment  of  im- 
munity in  the  last  twenty-five  years,  it  is  not  too  much 
to  expect  that  the  middle  of  the  twentieth  century  will 
see  the  production  of  immunizing  agents  for  practically 
all  infectious  diseases. 


CHAPTER  I 

DEFINITION,  MORPHOLOGY,  AND   PHYSIOLOGY 

Bacteriology  is  the  study  of  micro-organisms,  especi- 
ally in  their  relation  to  health  and  disease. 

Bacteria,  microbes,  micro-organisms,  or  germs  are 
practically  synonymous  terms,  designating  the  lowest 
form  of  plant  life  of  the  class  fungi.  They  are  minute 
single-celled  organisms  composed  of  protoplasm,  nuclear 
chromatin,  and  surrounded  by  a  cell  wall  containing 
cellulose  or  an  albuminous  membrane.  In  size  they 
average  i  mmm.  in  diameter  and  may,  therefore,  only 
be  seen  by  means  of  the  high-power  microscope. 

Form. — Bacteria  are  classified  according  to  their 
shape  as  follows: 

Bacilli,  cylindric  or  rod-shaped  organisms. 

Spirilla,  curved  or  spiral  rods. 

Cocci,  spheric  or  globular  organisms.' 

Flagella. — Attached  to  many  bacteria  are  found  fine 
thread-  or  hair-like  projections,  teimed  flagella,  which 
keep  up  a  constant  movement.  They  are  doubtless 
organs  of  locomotion,  as  they  are  found  most  frequently 
in  motile  bacteria. 

Motile  bacteria  are  those  forms  which  possess  the 
power  of  moving  themselves  from  place  to  place. 

16 


PLATE  1 


6  7 

Various  forms  of  microorganisms:  i,  Streptococci;  2,  staphylococci; 
3,  diplococci;  4,  tetracocci;  5,  spirilla;  6,  bacilli;  7,  bacilli  with  spores 
(Paul). 


DEFINITION,  MORPHOLOGY,  AND  PHYSIOLOGY      17 

Non-motile  bacteria  are  those  forms  which  do  not 
possess  the  power  of  locomotion.  ;, 

Reproduction. — In  common  with  all  living  organisms, 
bacteria  possess  the  power  of  reproducing  their  kind 
and  in  keeping  with  their  uncomplicated  structure; 
their  mode  of  reproduction  and  multiplication  is  corre- 
spondingly simple,  namely,  by  fission  or  simple  trans- 
verse division. 

Fission,  the  process  of  bacterial  reproduction,  takes 
place  as  follows:  The  cell  elongates,  an  indentation 
occurs  in  its  wall,  which  gradually  increases  in  depth 
until  the  cell  is  completely  divided,  and  two  cells  take 
the  place  of  one. 

Sporulation. — Under  certain  conditions  of  heat,  light, 
oxygen,  etc.,  conditions  detrimental  to  bacterial  activity, 
there  occur  in  some  bacteria  glistening,  highly  refractive 
bodies  termed  spores.  These  are  surrounded  by  a  tena- 
cious membrane  or  capsule,  and  when  the  spore  is 
fully  developed  the  remainder  of  the  bacterium  disin- 
tegrates and  disappears.  These  bodies  are  supposed  to 
represent  the  seed  or  resting  stage  of  the  plant's  existence 
and  is  a  means  whereby  the  organism  resists  deleterious 
influences.  It  is  not,  however,  a  means  of  multiplica- 
tion as  in  the  higher  plants,  as  each  bacterium  produces 
but  a  single  spore,  which,  under  favorable  conditions, 
again  develops  into  a  complete  bacterium,  which  may 
multiply  in  the  usual  manner  by  division. 

Owing  to  the  tenacious  character  of  its  membrane  the 
2 


18  BACTERIOLOGY 

spore  is  much  more  resistant  to  the  action  of  heat,  light, 
antiseptics,  and  other  injurious  agencies  than  are  the 
fully  developed  organisms.  They  resemble  in  this  re- 
spect the  seed  of  more  highly  organized  plants  which 
withstand  conditions  which  are  rapidly  fatal  to  the 
growing  plant. 


CHAPTER  II 

CONDITIONS   FOR   GROWTH   AND   PRODUCTS   OF  THE 
GROWTH  OF  BACTERIA 

Soil. — Bacteria  differ  in  their  selection  of  material 
upon  which  they  grow:  some  preferring  dead  organic 
matter,  others  living  only  on  the  tissues  of  living  or- 
ganisms. Some  grow  well  on  either  soil. 

Saprophytes  are  those  bacteria  which  grow  on  dead 
organic  matter;  for  this  reason  they  must  be  looked  upon 
as  benefactors  to  the  human  race.  It  is  through  their 
action  that  dead  bodies  and  other  highly  complex  or- 
ganic materials  are  broken  up  into  simpler  forms  and 
reduced  to  the  dust  from  whence  they  sprang;  thus  is 
the  earth  rid  of  its  carrion,  and  at  the  same  time  vegeta- 
tion, upon  which  man  and  the  higher  animals  subsist,  is 
furnished  with  the  simpler  compounds  of  nitrogen, 
hydrogen,  carbon  dioxid,  ammonia,  and  water  necessary 
for  its  growth. 

Parasitic  bacteria  live  upon  living  tissue  of  man  and 
other  animals,  and  must,  therefore,  be  looked  upon  as 
foes  of  mankind. 

Pathogenic  bacteria  are  those  bacteria  which  produce 
disease.  Inasmuch  as  practically  all  parasitic  bacteria 

19 


20  BACTERIOLOGY 

produce  disease  under  certain  conditions,  the  name 
pathogenic  bacteria  is  practically  synonymous  with 
parasitic  bacteria. 

N on- pathogenic  bacteria  are  those  which  do  not  pro- 
duce disease,  and  are,  for  the  most  part,  saprophytic. 

Stains. — Different  germs  behave  differently  toward 
various  pigments  when  brought  in  contact  with  them. 
Advantage  is  taken  of  this  fact  in  diagnosis,  germs  being 
differentiated  in  many  cases  by  their  staining  or  failing 
to  stain  with  a  certain  stain.  It  also  assists  in  recog- 
nizing their  presence  in  tissue  sections. 

Temperature. — Some  bacteria  grow  and  multiply  at  a 
temperature  as  low  as  o°  C.  (32°  F.),  while  others 
flourish  at  70°  C.  (158°  F.).  Pathogenic  bacteria  thrive 
better  at  about  the  temperature  of  the  human  body. 
While  cold  stops  the  growth  and  multiplication  of  these 
forms,  it  is  destructive  to  but  few  of  them.  Higher 
temperatures  they  do  not  endure  so  well,  and  a  tempera- 
ture of  60°  C.  (140°  F.)  for  a  prolonged  period  is  destruc- 
tive to  the  majority  of  forms.  A  much  higher  tempera- 
ture for  a  short  time  may  be  harmless,  and  freezing  and 
thawing  several  times  is  destructive  to  very  many  forms. 
Spores,  as  mentioned  before,  withstand  greater  degrees 
of  either  heat  or  cold  than  the  bacteria  themselves. 

Moisture  is  absolutely  necessary  to  the  growth  and 
multiplication  of  bacteria.  Drying  is  fatal  to  a  few 
forms,  as  the  cholera  spirillum,  but  merely  prevents  the 
growth  of  the  majority  of  species. 


GROWTH  AND  PRODUCTS  OF  BACTERIA     21 

Food. — Because  of  the  absence  of  chlorophyll  the 
majority  of  forms  of  bacteria  are  unable  to  obtain  their 
food-supply  of  carbon  and  nitrogen  from  the  air  as  do 
higher  plants,  but  must  obtain  it  from  the  organic 
matter  on  which  they  grow,  as  the  tissues  of  animals  or 
the  more  highly  organized  plants.  So  it  is  that  when 
bacteria  are  grown  artificially,  it  must  be  on  substances 
containing  these  necessary  food  elements,  as  gelatin, 
blood-serum,  animal  matter,  or  agar-agar  and  potatoes, 
highly  organized  plant  matter. 

Oxygen. — Different  bacteria  differ  in  their  behavior 
toward  oxygen. 

Aerobic  bacteria  are  those  which  cannot  exist  without 
the  presence  of  oxygen. 

Anaerobic  bacteria  are  those  to  whom  oxygen  is  fatal. 

Facultative  bacteria  are  those  which  can  exist  either 
with  or  without  oxygen.  Those  thriving  best  with 
oxygen,  but  which  can  exist  without,  are  called  facul- 
tative aerobes,  while  those  thriving  best  without  oxygen, 
though  existing  with  it,  are  termed  facultative  anaerobes. 

Light. — Direct  sunlight  and  strong  electric  light  are 
both  fatal  to  most  bacteria,  hence  the  importance  of  an 
abundance  of  sunlight  in  buildings  designed  for  human 
habitation. 

Products  of  Bacteria. — The  products  of  bacterial 
growth  are  varied  and  complex.  Some  produce  acids, 
as  the  butyric  and  lactic  acid  produced  respectively  by 
the  Bacillus  butyricus  and  Bacillus  acidi  lactici,  and 


22  BACTERIOLOGY 

the  production  of  acetic  acid  in  the  manufacture  of 
vinegar.  Others  still  produce  gases  and  odors,  some 
fragrant,  others  foul  and  noxious,  as  in  the  putrefactive 
processes. 

Poisons. — Just  as  certain  plants  of  the  higher  orders, 
such  as  nux  vomica,  nightshade,  and  others,  produce 
substances  which  are  poisonous  to  animal  organisms, 
so  do  these  lower  plant  forms  of  bacteria  produce  poisons 
which  in  many  instances  closely  resemble  the  poisonous 
alkaloids  of  the  higher  orders  of  plants. 

Ptomains. — Certain  of  the  complex  alkaloidal  poisons 
produced  by  saprophytic  bacteria  in  their  growth  on 
dead  organic  matter  are  called  ptomains.  The  ingestion 
of  food  containing  these  poisons  may  result  in  illness  or 
even  death. 

This  is  doubtless  the  only  exception  to  the  rule  that 
saprophytes  are  benefactors  of  mankind.  In  their  zeal 
to  rid  the  earth  of  organic  matter  saprophytic  germs 
often  attack  food-stuffs  which  man  has  not  yet  aban- 
doned. Upon  the  ingestion  of  meat,  shell-fish,  eggs, 
milk,  and  other  foods  wherein  such  bacterial  activity 
has  taken  place  ptomain-poisoning  results. 

Toxins.— The  products  of  parasitic  bacteria  are 
termed  toxins,  and  to  these  poisonous  substances  are 
due  most  of  the  pernicious  effects  of  bacterial  activity 
in  the  animal  body. 

Nearly  all  the  changes  in  the  organs  of  an  animal 
caused  by  bacterial  disease  can  be  reproduced  by  injec- 


GROWTH  AND  PRODUCTS  OF  BACTERIA      23 

tion  of  the  toxins  of  the  causative  germ,  and  in  many 
instances  most  of  the  symptoms  of  the  disease  may  be 
so  reproduced. 

Protozoa  are  minute  unicellular  animal  organisms 
closely  allied  to  bacteria,  but  differing  from  them  in 
their  mode  of  reproduction.  They  pass  through  a  com- 
plicated life-cycle  which  has  been  followed  completely 
only  in  the  malarial  protozoa.  There  occurs  first  an 
asexual  cycle  or  reproduction  which  takes  place  in  man, 
wherein  each  parasite  breaks  up  into  six  to  twenty 
spores  or  daughter-cells,  which  rapidly  develop  into 
full-grown  parasites.  The  periods  of  chills,  fever,  and 
sweats  of  malaria  correspond  to  these  periods  of  repro- 
duction of  the  parasite.  Then  there  occurs  a  sexual 
cycle  which  takes  place  in  an  intermediate  host,  the 
mosquito.  Male  and  female  elements  are  represented 
in  this  cycle  and  a  peculiar  spore  formed,  which,  when 
injected  into  man,  develops  into  the  complete  organism 
and  proceeds  to  pass  through  the  asexual  cycle  again. 


CHAPTER  III 

INFECTION,  SUSCEPTIBILITY,  AND  IMMUNITY 
Infection  is  understood  to  be  the  introduction  into 
an  organism  of  a  disease-producing  germ,  followed  by  the 
growth  and  development  of  the  germ,  and  the  production 
of  the  characteristic  effects  of  the  growth  and  develop- 
ment of  that  germ  upon  the  infected  organism.  From 
this  it  follows  that  every  introduction  of  a  germ  into  an 
organism  does  not  constitute  infection,  inasmuch  as 
disease  does  not  always  follow  such  introduction.  Be- 
fore disease  can  be  produced  by  the  introduction  into 
an  organism  of  any  particular  germ  certain  conditions 
must  exist.  In  other  words,  the  organism  must  be  sus- 
ceptible to  the  disease  and  the  germ  must  be  virulent. 
Susceptibility. — By  susceptibility  is  meant  the  ease 
or  difficulty  with  which  a  germ  develops  upon  a  certain 
organism.  Thus,  children  are  more  susceptible  to 
measles,  scarlet  fever,  and  whooping-cough  than  are 
adults. 

Immunity. — The  term  immunity  is  used  to  describe 
the  condition  of  absolute  lack  of  susceptibility.  If  an 
animal  is  so  constituted  that  the  germ  of  a  disease  will 
not  grow  upon  his  tissues  or  that  the  toxins  of  that  germ 
are  harmless  to  the  animal,  the  animal  is  immune  to  that 
particular  disease.  Thus,  man  is  immune  to  hog  cholera, 

24 


INFECTION,  SUSCEPTIBILITY,  AND  IMMUNITY       25 

symptomatic  anthrax,  and  hen  cholera,  while  all  animals 
except  man  and  monkeys  are  immune  to  syphilis. 

Such  immunity  is  termed  natural  immunity  in  contra- 
distinction to  acquired  immunity,  which  is  exemplified 
in  the  immunity  which  follows  an  attack  of  some  infec- 
tious disease,  as  measles,  scarlet  fever,  and  whooping- 
cough,  and  may  also  be  produced  artificially  by  vacci- 
nation, injection  of  antitoxin,  etc. 

Vaccination. — In  vaccination  the  subject  is  infected 
with  an  attenuated  or  modified  form  of  the  disease 
which,  however,  is  sufficient  to  give  immunity  to  further 
attacks.  Jenner,  by  infecting  individuals  with  cow-pox, 
which  is  a  modified  form  of  small-pox  caused  by  the 
growth  of  the  small-pox  germ  on  an  unfavorable  host, 
the  cow,  procured  immunity  to  small-pox.  Pasteur 
produced  a  vaccine  against  anthrax  by  subjecting  an 
anthrax  culture  to  high  temperature  for  twenty  days, 
thus  so  destroying  its  virulence  that  an  animal  infected 
with  such  a  culture  had  a  very  mild  attack  of  anthrax, 
which,  however,  was  sufficient  to  render  it  immune  to 
further  attacks  of  anthrax. 

Bacteriolysis. — It  has  been  found  that  normal  blood- 
serum  possesses  the  power  to  destroy  bacteria  under 
certain  conditions.  This  property  is  termed  bacterio- 
lysis. Various  substances  in  the  serum  are  concerned 
in  such  destruction,  such  as  alexins,  lysins,  etc.  Just 
what  part  each  and  every  one  of  these  substances  play 
in  bacteriolysis  is  not  as  yet  definitely  known. 


26  BACTERIOLOGY 

Agglutinins. — There  is  found  in  the  blood-serum  of 
animals  suffering  from  certain  diseases  substances  which, 
when  such  serum  is  added  to  a  liquid  culture  of  the  germ 
of  that  disease,  cause  a  clumping  together  into  a  motion- 
less mass  of  the  bacteria  of  the  culture.  Advantage  is 
taken  of  this  in  the  so-called  Widal  test  for  typhoid 
fever,  which  will  be  described  later. 

Phagocytosis. — Metchnikoff  in  his  studies  discovered 
that  certain  body  cells,  chiefly  the  polynuclear  leuko- 
cytes, possess  the  power  of  surrounding  and  ingesting 
foreign  substances,  such  as  carbon,  dust,  and  other  for- 
eign bodies  inhaled  or  driven  into  the  tissues  by  injury, 
also  bits  of  degenerated  or  dead  tissue,  and,  most  im- 
portant of  all,  bacteria.  These  cells  he  called  phago- 
cytes and  the  process  phagocytosis. 

Metchnikoff  believed  that  recovery  from  disease  and 
subsequent  immunity  depended  on  the  ability  of  the 
phagocytes  to  destroy  the  invading  bacteria,  and  that 
when  the  phagocytes  were  unequal  to  the  task  the  bac- 
teria conquered  and  death  ensued.  It  was  found,  how- 
ever, that  in  some  instances  the  leukocytes  failed  to 
attack  the  invading  germ.  Bail  found  this  to  be  due  par- 
tially to  certain  products  of  bacterial  activity  which  he 
termed 

Aggressins,  the  property  of  which  seemed  to  be  to 
render  the  bacteria  more  aggressive,  while  paralyzing 
or  checking  the  activity  of  the  phagocytes. 

Opsonins.— Wright  and  Douglas  in  1903  found  that 


INFECTION,  SUSCEPTIBILITY,  AND  IMMUNITY       27 

phagocytosis  depended  upon  the  presence  in  the  blood 
of  substances  which  they  called  opsonins,  which  so  act 
upon  live  bacteria  as  to  make  them  fit  food  for  the  phago- 
cytes, thus  producing  just  the  opposite  effect  from  that 
of  the  aggressins.  They  found  that  these  opsonins  differ 
for  the  different  varieties  of  bacteria,  that  an  opsonin 
for  one  variety  of  germ  had  no  effect  upon  germs  of 
another  variety. 

Bacterial  Vaccines. — They  further  found  that  by 
injecting  dead  cultures  of  a  germ  the  opsonins  for  that 
germ  were  increased,  and  phagocytosis  stimulated  ac- 
cordingly. These  dead  cultures  prepared  for  such  use 
were  called  bacterial  vaccines. 

Antitoxin. — When  any  plant  organism  grows  on  a  [ 
certain  soil  for  any  length  of  time  it  produces  substances 
detrimental  to  its  own  life  and  growth.  The  farmer 
recognizes  this  in  his  rotation  of  crops.  So  bacteria 
grown  too  long  on  the  same  artificial  media  cease  to 
flourish  and  even  die.  In  the  animal  body  this  doubtless 
occurs,  but  of  more  importance  is  the  fact  that  there 
are  produced  by  the  body  cells  antibodies  or  substances 
antagonistic  to  bacterial  growth  and  antidotal  to  their 
poisons.  Whether  produced  by  the  phagocytes  or  by 
the  fixed  tissue  cells,  or  by  both,  is  not  definitely  known, 
nor  is  it  important  to  us.  The  fact  remains  that  there 
is  produced  in  the  course  of  certain  diseases  certain  sub- 
stances called  antitoxins,  which  may  be  recovered  from 
the  blood  of  the  animal  which  has  been  the  subject  of  the 


28  BACTERIOLOGY 

disease,  and  which  may  be  introduced  into  the  blood  of 
other  animals  suffering  from  this  same  disease,  where 
they  unite  with  the  toxins  of  the  disease,  rendering  them 
harmless.  At  the  same  time  they  so  affect  the  causative 
germ  as  to  check  its  growth,  or  else  the  germ  exhausts 
its  soil  or  is  attacked  by  the  leukocytes,  which  are  no 
longer  paralyzed  by  the  toxins  and  aggressins;  at  any 
rate,  its  activity  ceases  and  recovery  occurs.  The  most 
important  antitoxins  are  those  of  diphtheria  and  of 
tetanus,  of  which  more  will  be  said  later. 

Theories  of  Immunity. — From  the  contents  of  the 
foregoing  pages  it  will  be  gathered  that  several  theories 
have  been  adduced  in  explanation  of  the  phenomenon 
of  immunity. 

It  will  doubtless  eventually  be  found  to  depend  upon 
the  presence  in  the  blood  of  these  wonderful  substances, 
opsonins  and  antitoxins,  either  alone  or  in  combination. 
It  is  a  fact  already  known  that  the  injection  of  antitoxin 
renders  an  individual  immune  to  diphtheria  for  a  greater 
or  less  period  of  time,  and  raising  the  opsonic  index  by 
vaccination  against  typhoid  fever  has  been  practised 
with  great  success,  rendering  the  vaccinated  individual 
immune  to  the  disease  in  some  instances  for  years. 
It  may  be  that  in  some  diseases  the  immunity  is  the 
result  of  phagocytosis,  while  in  others  it  is  due  to  the 
antibodies,  or,  perhaps  in  some,  a  combination  of  both. 


CHAPTER  IV 

EXAMINATION   OF  BACTERIA,  MICROSCOPIC  DIAG- 
NOSIS, ETC 

INASMUCH  as  only  those  nurses  who  become  surgical 
assistants  or  laboratory  workers  will  be  concerned  in  the 
details  and  specific  methods  of  bacterial  examination 
and  technic,  no  attempt  will  be  made  here  to  present 
such  methods  in  detail.  Those  who  are  interested  in 
such  laboratory  technic  are  referred  to  the  more  pre- 
tentious works  for  physicians  and  medical  students. 

Owing  to  their  minute  size,  bacteria  can  only  be  ex- 
amined by  means  of  a  high-power  microscope,  assisted 
by  a  device  known  as  an  oil-immersion  lens,  in  which  a 
drop  of  cedar  oil  is  interposed  between  the  lens  and  the 
cover-glass,  beneath  which  is  the  object  to  be  observed, 
the  purpose  of  such  device  being  to  concentrate  all  of 
the  rays  of  light  emerging  from  the  specimen  observed. 
In  addition  there  is  needed  an  Abbe  condenser,  a  device 
for  concentrating  the  rays  upon  the  object  viewed. 

Being  provided  with  the  proper  apparatus,  the  speci- 
men may  be  examined  in  several  ways.  If  the  specimen 
be  from  a  liquid  culture,  a  drop  may  be  taken  on  a 
platinum  loop  placed  between  a  cover-glass  and  slide 


30  BACTERIOLOGY 

and  examined  with  the  oil-immersion  lens.  Or  it  may 
be  examined  by  the  hanging-drop  method.  In  this 
method  a  slide  is  used  in  which  a  small  depression  is 
hollowed  out.  The  drop  of  culture  or  pus  to  be  exam- 
ined is  placed  upon  the  cover-glass,  which  is  then  inverted 
over  the  depression,  and  the  drop  allowed  to  hang  free 
in  the  space  between  the  cover-glass  and  slide.  By  this 
means  the  movement  of  motile  bacteria  and  agglutina- 
tion, as  in  the  Widal  test,  may  be  observed.  By  sealing 
the  edges  of  the  cover-glass,  evaporation  is  prevented, 
and  the  specimen  may  be  studied  for  days,  and  such 
processes  as  spore  formation  and  fission  observed. 

If  it  be  desired  to  stain  the  specimen,  it  must  be  pre- 
pared in  the  form  of  a  smear.  A  small  amount  of  the 
material  is  taken  on  a  platinum  loop  (if  liquid)  or  needle 
(if  solid)  and  smeared  over  the  surface  of  a  cover-glass. 
It  is  then  fixed  by  being  passed  through  an  open  flame, 
thus  coagulating  the  albumin  of  the  material  and  fasten- 
ing it  to  the  cover-glass.  The  proper  staining  fluid  is 
then  flowed  over  the  smear  and  allowed  to  remain  the 
required  length  of  tune,  with  or  without  the  application 
of  heat,  according  to  the  stain  used  and  the  specimen 
examined.  When  stained,  it  is  placed  upon  a  slide  with 
a  drop  of  water  interposed,  or  if  it  be  desired  to  mount  the 
specimen  permanently,  a  drop  of  Canada  balsam  is 
used  instead  of  the  water  between  the  cover-glass 
and  slide,  and  the  specimen  examined  in  the  usual 
manner. 


EXAMINATION  OF  BACTERIA,  DIAGNOSIS,  ETC.         31 

If  the  specimen  to  be  examined  be  tissue,  a  compli- 
cated process  of  hardening  and  embedding  in  paraffin  or 
celloidin  must  be  carried  out,  after  which  sections  or 
slices  so  thin  as  to  be  translucent  are  cut  from  the  speci- 
men, the  paraffin  or  celloidin  dissolved  out,  and  the  sec- 
tion stained  by  immersion  in  solutions  of  certain  dyes. 
It  is  then  mounted  in  Canada  balsam  and  examined  in 
the  usual  way. 


CHAPTER  V 

BACTERIA  IN  DISEASE 

ATTENTION  has  already  been  called  to  the  role  played 
by  saprophytic  bacteria  in  ridding  the  world  of  the  dead 
bodies  of  plants  and  animals.  Mention  may  also  be 
made  of  the  use  made  of  bacteria  in  the  industries,  as 
the  bacillus  whose  growth  in  cream  imparts  the  agree- 
able flavor  to  butter  and  cheese,  the  bacteria  used  in 
the  manufacture  of  vinegar;  even  in  tilling  the  soil  ad- 
vantage is  now  taken  of  the  property  of  nitrifying 
bacteria  to  extract  nitrogen  from  the  atmosphere  to 
enrich  the  soil  and  take  the  place  of  chemical  fertilizers. 

But  to  the  nurse  the  most  important  thing  in  connec- 
tion with  the  whole  subject  of  bacteriology  is  the  part 
played  by  bacteria  in  the  production  of  disease.  By  far 
the  greater  number  of  diseases  to  which  the  animal  world 
is  heir  are  due  to  bacteria,  and  even  the  vegetable  is  not 
exempt,  and  has  its  germ  diseases. 

Koch's  Rules. — Koch  laid  down  certain  rules  which 
he  held  must  be  complied  with  to  prove  that  any  bac- 
terium was  the  cause  of  any  particular  disease: 

First:  It  must  be  found  in  the  tissues  or  secretions  of 
the  animal  having  the  disease. 


BACTERIA  IN  DISEASE  33 

Second:  The  germ  from  the  affected  animal  must  be 
grown  in  pure  culture  on  artificial  media. 

Third:  Such  culture  should  produce  the  disease  when 
introduced  into  a  healthy  animal. 

Fourth:  The  same  organism  must  be  recovered 
from  the  tissues  or  secretions  of  the  animal  thus  in- 
fected. 

Infectious  Diseases. — Any  disease  caused  by  the 
growth  and  multiplication  of  a  micro-organism  on  the 
tissues  of  the  animal  having  the  disease  is  called  an  in- 
fectious disease.  Not  all  infections  are  due  to  bacteria, 
since  malaria  and  yellow  fever  are  due  to  minute  animal 
organisms. 

Contagious  Diseases. — A  disease  which  is  acquired 
by  direct  or  indirect  contact  with  an  individual  having 
the  disease  is  termed  a  contagious  disease.  All  conta- 
gious diseases  are  infectious,  but  not  all  infectious  dis- 
eases are  contagious.  The  distinction  is  more  apparent 
than  real  and  is  not  important. 

Avenues  of  Infection. — The  embryo  may  be  infected, 
though  rarely,  through  the  ovum  or  the  spermatozoa. 
Infection  with  syphilis  may  thus  occur.  The  fetus  may 
be  thus  infected  through  the  placenta  with  small-pox, 
scarlet  fever,  tuberculosis,  etc.,  when  the  mother  suffers 
from  the  disease.  Bacteria  may  gain  entrance  to  the 
body  through  the  healthy  skin  in  rare  instances;  usually 
it  is  through  minute  wounds  of  the  skin.  The  mucous 
membranes  of  the  mouth,  nose,  throat,  bronchi,  ali- 

3 


34  BACTERIOLOGY 

mentary  canal,  urethra,  vagina,  etc.,  offer  less  resistance 
than  does  the  skin  to  the  passage  of  germs. 

After  introduction  the  bacteria  may  remain  localized 
and  multiply  at  the  point  of  entrance,  or  be  rapidly 
disseminated  through  the  body  and  produce  lesions  at 
distant  points  from  the  place  of  entrance. 

Period  of  Incubation. — After  the  introduction  of  the 
germ  of  an  infectious  disease  into  an  animal  organism 
a  variable  time  elapses  before  the  advent  of  the  symp- 
toms of  the  disease.  This  period  is  termed  the  period  of 
incubation,  and  is  fairly  constant  for  each  particular 

disease. 

SOURCES  OF  INFECTION 

Dust  is  a  frequent  source  of  infection.  The  bacteria 
of  tuberculosis,  anthrax,  influenza,  and  the  acute  infec- 
tious diseases  may  attach  themselves  to  dust  particles 
and  be  wafted  about. 

Air. — Pure  air  of  the  mountain-tops  and  mid-ocean 
is  free  from  germs.  Air  is,  therefore,  a  source  of  infec- 
tion just  in  proportion  to  the  amount  of  dust,  carbon, 
and  other  solid  particles  floating  in  it. 

Water  contaminated  with  sewage  is  a  frequent  source 
of  infection,  especially  of  typhoid,  cholera,  and  dysen- 
tery. 

Milk  is  an  excellent  culture-medium  in  itself,  and  is 
a  source  of  infection  in  typhoid  fever,  scarlet  fever, 
diphtheria,  and  probably  tuberculosis,  especially  in 
infants.  Hence  the  necessity  of  rigid  medical  inspec- 


BACTERIA  IN  DISEASE  35 

tion  and  supervision  of  dairies,  milk  depots,  and  other 
sources  of  milk  and  cream  supply. 

Food. — Uncooked  foods  may  carry  infection.  Raw 
oysters,  which  are  sometimes  fattened  on  sewage,  are 
a  prolific  source  of  typhoid  infection.  Celery,  lettuce, 
radishes,  and  fruits  are  occasional  sources  of  infection, 
especially  if  exposed  to  dust  and  flies. 

Flies,  because  of  their  pernicious  habit  of  alighting 
upon  and  feeding  upon  all  manner  of  filth  and  dis- 
charges, are  a  most  formidable  source  of  infection  of  all 
kinds,  and  especially  of  typhoid  fever.  Cholera,  diph- 
theria, tuberculosis,  scarlet  fever,  and  other  infections 
may  frequently  be  traced  to  flies. 

Fleas,  bed-bugs,  and  ticks  are  less  frequent  sources  of 
infection.  The  flea  transmitting  bubonic  plague  from 
rats  to  rats  and  from  rats  to  man,  while  the  tick  is  the 
source  of  infection  of  a  disease  peculiar  to  certain  moun- 
tainous districts  of  Montana,  Wyoming,  and  Idaho, 
called  spotted  fever.  It  is  also  the  cause  of  Texas  fever 
in  cattle. 

Dogs  and  Cats. — These,  as  well  as  tame  rabbits, 
guinea-pigs,  and  other  domestic  pets,  may  carry  dis- 
ease germs  on  their  coats  or  feet. 

Rats,  Mice,  and  Squirrels. — Rats  are  the  great  source 
of  infection  in  bubonic  plague,  having  the  disease  them- 
selves and  scattering  it  broadcast  by  means  of  the  fleas 
with  which  they  are  infested.  Ground  squirrels  have 
recently  been  found  to  be  susceptible  to  plague,  and 


36  BACTERIOLOGY 

are  becoming  a  very  serious  menace  to  certain  Pacific- 
coast  states. 

Soil. — Bacteria  most  frequently  found  in  soil  are  the 
Staphylococcus  aureus,  bacillus  of  tetanus,  bacillus  of 
malignant  edema,  and  anthrax.  The  most  important, 
from  a  surgical  standpoint,  being  the  tetanus  germ. 


CHAPTER  VI 

PYOGENIC  BACTERIA,  PYEMIA,  SAPREMIA,  SEPTI- 
CEMIA,   INFECTIOUS  DISEASES 

PYOGENIC  BACTERIA 

WHILE  almost  any  germ  may  produce  suppuration 
under  certain  conditions,  there  are  certain  forms  which 
are  particularly  prone  to  cause  pus  formation.  These 
are  termed  pyogenic  bacteria.  The  more  important 
pyogenic  bacteria  are  the  following: 

Staphylococcus  Pyogenes  Aureus  (the  Golden-yellow 
Coccus). — This  is  a  facultative  anaerobic  germ,  found 
in  soil,  dust,  water,  the  alimentary  canal,  on  and  hi  the 
superficial  layers  of  the  skin,  especially  of  the  axilla  and 
perineum.  It  is  the  cause  of  75  per  cent,  of  acute 
abscesses,  as  boils,  felons,  etc.  It  is  also  the  cause  of 
certain  forms  of  osteomyelitis  and  of  pyemia. 

Staphylococcus  Pyogenes  Albus  (White  Coccus). — 
A  Staphylococcus  more  feeble  in  power  than  the  yellow 
coccus.  A  variety  of  the  white  coccus,  called  the 
Staphylococcus  epidermidis  albus,  found  constantly  on 
the  skin  and  in  its  deep  layers,  is  the  usual  cause  of 
stitch  abscess. 

37 


38  BACTERIOLOGY 

Other  staphylococci  are  the  Pyogenes  citreus,  the 
lemon-yellow  coccus,  Staphylococcus  cereus  flavus  and 
cereus  albus,  and  Staphylococcus  flavescens,  all  of 
which  are  of  feeble  pyogenic  power. 

Streptococcus  Pyogenes. — A  facultative  anaerobic 
bacterium  found  in  the  nasal  passages,  vagina,  and  ure- 
thra. It  is  a  much  more  dangerous  germ  than  the  Staphy- 
lococcus and  is  the  cause  of  spreading  inflammations, 
cellulitis,  puerperal  fever,  erysipelas,  otitis  media,  mas- 
toiditis,  septicemia,  and  pyemia. 

Bacillus  Pyocyaneus  (Bacillus  of  Green  Pus).— 
Found  in  the  skin,  in  the  feces,  and  in  pus;  usually  in 
mixed  infections,  in  otitis  media,  peritonitis,  appendi- 
citis, etc. 

SEPTICEMIA  OR  SEPTIC  INFECTION 

In  ordinary  suppuration  the  pyogenic  toxins  alone 
enter  the  circulation,  causing  the  fever  and  other  con- 
stitutional disturbances.  In  sapremia  the  ptomains  of 
saprophytic  bacteria,  growing  on  blood-clots,  stagnant 
secretions,  etc.,  enter  the  circulation,  causing  disturb- 
ance, but  in  true  septic  infection  both  pyogenic  germs 
and  their  toxins  enter  the  circulation.  Manifestly, 
such  a  condition  is  the  most  serious  of  the  three,  and 
the  most  to  be  feared  of  all  surgical  accidents. 

Pyemia. — The  condition  of  septicemia  in  which  there 
are  formed  metastatic  abscesses  from  septic  material 
in  the  circulation  becoming  implanted  in  various  parts 


SEPTICEMIA  OR  SEPTIC  INFECTION  39 

of  the  body  is  termed  pyemia.  Pyemia  is,  therefore, 
only  a  form  of  septicemia. 

Mixed  Infection. — In  any  pus  infection  we  are  apt  to 
have  a  mixed  infection,  with  several  pyogenic  germs, 
rather  than  a  pure  culture  of  any  one  germ,  one  germ 
seeming  to  pave  the  way  or  prepare  the  field  for  the 
growth  of  another.  Thus  the  staphylococcus  and  strep- 
tococcus are  frequently  found  in  the  same  pus  foci, 
while  the  lesions  of  tuberculosis  and  of  pneumonia  are 
frequently  infected  with  pus  cocci. 

Infectious  Diseases. — A  list  is  herewith  given  of  the 
more  important  diseases  of  man  caused  by  bacteria. 
No  mention  can  be  made,  in  the  space  at  our  disposal, 
of  the  infectious  diseases  of  the  lower  animals: 

Tuberculosis.  Septicemia. 

Influenza.  Pyemia. 

Pneumonia.  Gonorrhea. 

Diphtheria.  Malta  fever. 

Cholera.  Leprosy. 

Bubonic  plague.  Cerebrospinal  meningitis. 

Tetanus.  Syphilis. 

Typhoid  fever.  Relapsing  fever. 

Glanders.  Whooping-cough. 

Anthrax. 

Malaria,  yellow  fever,  and  amebic  dysentery  are 
caused  by  minute  animal  organisms  called  protozoa. 


40  BACTERIOLOGY 

Mumps,  measles,  scarlet  fever,  small-pox,  chicken-pox, 
rheumatism,  beriberi,  pellagra,  and  infantile  paralysis 
will  all  be  added  some  day  to  the  list  of  diseases  whose 
specific  germ  is  known.  Indeed,  so  rapid  is  the  advance 
along  these  lines  that  a  list  which  may  be  considered  com- 
plete to-day  may  be  far  from  so  to-morrow. 


CHAPTER  VII 

PATHOGENIC    BACTERIA   AND   DISEASES   CAUSED  BY 

THEM 

MiCROCOCCI 

Micrococcus  Lanceolatus  (Micrococcus  Pneumonias, 
Diplococcus  Pneumonia,  Pneumococcus  of  Frankel). 
— A  non-motile,  non-spore-forming  coccus,  occurring 
in  pairs.  It  is  the  cause  of  lobar  pneumonia,  also  of 
otitis  media,  ulcer  of  the  cornea,  endocarditis,  mastoid- 
itis,  and  meningitis.  It  is  found  in  the  mouths  of 
healthy  individuals,  though  it  seems  not  to  be  virulent 
under  such  conditions.  It  is  found  in  great  numbers  in 
the  sputum  of  lobar  pneumonia  and  in  the  lungs,  where 
it  produces  its  characteristic  lesions  of  inflammation — 
consolidation  accompanied  by  high  temperature.  Sus- 
ceptibility to  infection  is  increased  by  lowered  vitality 
from  whatever  cause,  as  age,  exposure  to  cold  and  wet, 
other  diseases,  as  influenza  and  tuberculosis,  or  applica- 
tion of  other  irritants  to  the  respiratory  mucosa. 

Serum  treatment  has  proved  ineffectual.  Sputum  and 
excretions  should  be  disinfected,  as  should  the  room 
of  the  pneumonia  patient.  There  is  great  danger  not 
only  of  others  contracting  the  disease,  but  of  wound 

41 


42  BACTERIOLOGY 

infection  and  mixed  infection  of  other  suppurative  con- 
ditions. 

Diplococcus  Intracellularis  Meningitidis. — The  cause 
of  cerebrospinal  meningitis. 

Source  of  Infection. — Doubtless  patients  having  the 
disease,  dust,  and  air.  The  avenue  of  infection  is  prob- 
ably the  mucous  membrane  of  the  nasopharynx.  It 
is  found  in  the  cerebrospinal  fluid,  and  the  lesions  are 
purulent  inflammation  of  the  pia  and  arachnoid,  mem- 
branes of  the  brain,  and  spinal  cord.  High  temperature, 
convulsions,  and  death  in  80  to  90  per  cent,  of  the  cases, 
with  permanent  paralysis  of  various  functions  in  those 
who  recover.  Prevention  of  infection  includes  disin- 
fection of  various  discharges,  fumigation  of  rooms,  and 
cleanliness  of  nasopharynx. 

Serum  Treatment. — Flexner,  working  in  the  Rocke- 
feller Institute,  has  recently  perfected  a  serum  which  is 
curative  in  a  large  proportion  of  cases.  Its  use  has 
already  reduced  the  mortality  of  cases  from  80  to  90 
per  cent,  to  about  25  per  cent.,  and  it  is  highly  probable 
that  its  early  use  and  more  perfect  technic  will  give  a 
still  greater  reduction  of  mortality. 

Micrococcus  Melitensis. — A  non-motile  coccus,  the 
cause  of  Malta  or  Mediterranean  fever,  a  disease  occur- 
ring on  the  Island  of  Malta,  along  the  Mediterranean, 
in  Porto  Rico,  the  Philippine  Islands,  and  India. 

Source  of  Infection. — In  a  large  percentage  of  the 
cases  goats'  milk  has  been  found  to  be  the  source  of  in- 


PATHOGENIC  BACTERIA  AND  DISEASES  43 

fection.  The  germs  are  found  in  large  numbers  in  the 
spleen  of  infected  animals.  In  man  it  causes  a  chronic 
remittent  fever,  with  pains  in  the  joints  and  profuse 
sweating.  The  agglutination  test  is  positive  and  is 
used  as  a  means  of  diagnosis. 

Micrococcus  Gonorrhoeas  (Gonococcus  of  Neisser). 
— A  flattened  coccus  occurring  in  pairs. 

Source  of  Infection. — Gonorrheal  pus.  It  is  usually 
acquired  through  sexual  intercourse,  though  contact 
with  the  pus  in  any  manner  will  infect  mucous  membrane. 
It  causes  purulent  inflammation  of  the  urethra,  vagina, 
uterine  adenexa,  conjunctivitis,  ophthalmia  neonatorum, 
or  conjunctivitis  of  the  newborn.  Here  the  germ  comes 
in  contact  with  the  eyes  of  the  child  during  its  descent 
through  the  birth-canal,  which  is  the  seat  of  gonorrhea. 

It  is  also  the  cause  of  arthritis  or  gonorrheal  rheu- 
matism and  endocarditis;  30  per  cent,  of  the  blind- 
ness in  the  United  States  is  considered  to  be  due  to 
this  cause. 

Preventive  measures  include  disinfection  of  discharges 
and  hands.  Sexual  abstinance.  In  the  newborn,  where 
gonorrhea  of  the  mother  is  suspected,  Credos  method 
should  be  employed.  This  consists  of  the  instillation  of 
2  per  cent,  solution  of  silver  nitrate  immediately,  neu- 
tralized with  salt  solution.  Protargol  may  be  used  in 
place  of  the  silver  nitrate.  Opsonic  therapy  has  recently 
been  used  with  success  in  the  treatment  of  this  disorder, 
and  vaccines  are  now  on  the  market. 


44  BACTERIOLOGY 

BACILLI 

Bacillus  Tuberculosis. — The  discovery  of  the  tubercle 
bacillus  by  Koch  in  1882  may  almost  be  said  to  mark  an 
epoch  in  the  history  of  medicine.  It  is  a  slender  rod- 
shaped  anaerobic  germ  found  in  the  sputum,  pus,  and 
tissues  of  tuberculous  lesions.  It  is  pathogenic  to  man, 
apes,  cows,  sheep,  horses,  rabbits,  guinea-pigs,  and  field 
mice.  Goats  and  dogs  are  immune. 

Infection  occurs  through  the  nasopharynx,  lungs,  and 
gastro-intestinal  canal.  Particles  of  dried  sputum  may 
be  inhaled  and  infection  take  place  in  the  lungs,  the 
most  frequent  location  of  the  trouble,  or  they  may  be 
ingested  with  the  food,  and  infection  take  place  through 
the  tonsils  or  neighboring  lymph-glands,  or  through 
the  intestinal  mucosa,  especially  in  infants. 

Entering  the  blood  through  the  intestinal  mucosa, 
they  may  become  located  in  most  any  of  the  organs  of 
the  body.  The  most  frequent  locations  being  the  lungs, 
lymph-nodes,  bones,  intestines,  skin,  meninges,  perito- 
neum and  pleura,  testicles,  ovaries,  kidneys.  Milk  is, 
no  doubt,  a  frequent  source  of  infection,  becoming  con- 
taminated in  handling.  At  present  there  is  some  ques- 
tion of  the  transmissibility  of  bovine  tuberculosis  to 
humans,  Koch  having  claimed  it  to  be  a  negligible  factor, 
while  others  look  upon  it  as  a  frequent  source  of  infec- 
tion, especially  in  children.  Cattle  may  be  infected 
with  the  human  variety,  but  it  is  manifestly  impossible 


PATHOGENIC  BACTERIA  AND  DISEASES  45 

to  reverse  the  experiment  and  inoculate  human  beings 
with  the  bovine  variety. 

Pigs,  monkeys,  rabbits,  and  most  other  animals  are  sus- 
ceptible to  the  bovine  variety,  and  it  seems  unlikely  that 
man  alone  should  be  exempt.  Local  infections  of  the 
skin  with  the  bovine  variety  have  occurred  in  butchers, 
but  the  infection  has  differed  in  its  manifestations  from 
similar  infections  with  the  human  type.  The  case  has 
not  been  proved,  however,  and  until  more  definite  data 
is  at  hand,  every  precaution  should  be  taken  to  prevent 
infection  with  the  bovine  type  of  the  disease. 

The  source  of  bovine  infection,  if  it  does  occur,  is 
not  direct  from  the  udder  to  the  milk,  except  in  rare 
instances  of  tuberculosis  of  the  udder,  but  indirectly, 
by  way  of  the  intestinal  canal.  The  most  frequent  seat 
of  the  disease  in  cows,  as  in  man,  is  in  the  lungs.  The 
cow  does  not  expectorate  the  material  coughed  up,  but 
swallows  it.  The  feces  are,  therefore,  teeming  with  the 
germs  in  an  infected  cow.  Unless  great  care  is  exercised 
in  stabling  and  milking,  the  milk  is  easily  contaminated 
with  the  feces,  which  may  be  found  in  the  dust  and  air 
of  the  stable. 

The  sputum  of  tuberculous  patients  should  be  received 
in  paper  sputum  cups  and  destroyed  by  burning.  All 
discharges  from  tuberculous  foci  should  be  destroyed. 
Fresh  air  and  sunlight  are  detrimental  to  the  growth  and 
development  of  the  germ  and  should  be  courted  ac- 
cordingly. Out-door  sleeping  and  living,  winter  and 


46  BACTERIOLOGY 

summer,  are  the  most  important  measures  with  which 
to  combat  the  disease,  and  likewise  to  prevent  infection. 

Tuberculin  was  formerly  extolled  as  a  curative  meas- 
ure, but  disastrous  results  in  many  cases  caused  its 
abandonment.  A  new  form  of  the  preparation  is  again 
being  used  with  success  in  properly  selected  cases.  Its 
most  important  use,  however,  is  as  a  diagnostic  measure. 
Injection  of  it  into  a  subject  having  the  disease  gives 
rise  to  elevation  of  temperature.  This  is  called  a  pos- 
itive reaction. 

Calmette's  reaction  consists  hi  placing  a  small  amount 
of  tuberculin  on  the  conjunctiva.  In  a  few  hours,  if 
tuberculosis  be  present,  a  more  or  less  decided  reaction 
or  congestion  occurs.  Tuberculosis  has  been  called  the 
great  white  plague;  i  person  in  every  10  dies  of  it. 

Recent  statistics  of  postmortem  examinations  made 
abroad  show  that  90  per  cent,  of  adult  bodies  contained 
either  active  or  healed  foci  of  tuberculosis.  The  Ger- 
mans have  a  saying  to  the  effect  that  "Everybody  has 
a  little  tuberculosis."  All  of  which  goes  to  show  how 
widespread  is  the  disease  and  how  curable,  as  many 
healed  lesions  of  tuberculosis  are  found  in  people  who 
have  lived  and  died  unconscious  of  having  had  the 
disease. 

Bacillus  Diphtheria  (Klebs-Loffler  Bacillus).— A  non- 
motile,  non-spore-forming,  dumbbell-shaped  bacillus. 
The  germ  is  widely  distributed.  It  is  found  in  healthy 
throats  and  in  the  throats  of  those  who  have  had  the 


PLATE  Ii 


Bacillus     pneumonise,  (X  800) 
a,  as  seen  in  sputum. 


Bacillus  influenzae  in  nasal  secre- 
tion, (X  1000). 


Micrococcus  meningitidis 
cerebrospinalis,  (X  1000). 


Micrococcus    pyogenes    aureus 
(X  1000). 


Bacillus  typhosus,  a,  ordinary 
form  ( X  1000)  ;  b,  flagellate 
form  (X  1500). 


Bacillus  tuberculosis;  «,(Xiooo); 
b,  ramified  or  branching  form. 


(Lehmann  and  Neumann.) 


PATHOGENIC  BACTERIA  AND  DISEASES  47 

disease  for  months  after  recovery.  The  usual  site  of 
infection  is  the  mucous  membrane  of  the  throat  and  naso- 
pharynx, though  wounds  in  any  location  may  be  infected. 

The  germ  gains  entrance  through  some  alteration 
of  the  mucous  membrane  and  proceeds  to  produce  its 
characteristic  lesion,  namely,  a  fibrinous  membrane, 
which  rapidly  spreads  over  the  contiguous  mucous 
membrane.  The  germs  do  not  enter  the  body,  but  re- 
main localized  at  the  site  of  infection.  Their  toxins, 
however,  are  absorbed,  causing  temperature,  exhaustion, 
and  occasionally  paralysis  of  certain  muscles,  as  those 
of  the  palate,  vocal  cords,  and  heart. 

Bacteriologic  Diagnosis. — Boards  of  health  furnish  an 
outfit  containing  two  test-tubes.  In  one  is  a  sterile 
swab  and  in  the  other  blood-serum.  A  piece  of  the 
membrane  or  some  of  the  secretion  from  the  throat  is 
obtained  on  the  swab  and  smeared  over  the  blood-serum 
in  the  tube,  which  is  stoppered  and  sent  to  the  laboratory 
where  it  is  placed  in  the  incubator  for  twelve  hours, 
when,  if  the  case  be  diphtheria,  the  germ  may  be  recog- 
nized by  examination  of  the  culture  with  the  micro- 
scope. 

It  is  difficult  to  differentiate  a  diphtheritic  infection 
from  a  simple  tonsillitis  or  other  angina  at  an  early 
stage  except  by  this  means.  As  the  success  of  antitoxin, 
which  is  the  only  treatment  relied  upon  at  this  time, 
depends  upon  its  early  administration,  this  means  of 
diagnosis  is  important.  When  the  infection  is  located 


48  BACTERIOLOGY 

in  or  extends  into  the  larynx,  the  condition  is  called 
membranous  croup  or  laryngeal  diphtheria.  The  mem- 
brane may  close  the  larynx  and  death  from  suffocation 
result  unless  intubation  or  tracheotomy  is  performed. 

Prevention  of  Infection. — An  absolutely  certain  pre- 
ventive of  infection  is  an  immunizing  dose  of  antitoxin. 
An  injection  of  from  1000  to  3000  units  is  considered 
sufficient  for  immunization,  while  curative  doses  range 
from  3000  to  20,000  units,  depending  on  the  severity 
of  the  case  and  the  stage  at  which  the  antitoxin  is  ad- 
ministered. 

A  rare  and  curious  condition  exists  in  some  individuals, 
in  which  the  person  is  said  to  be  sensitized  to  horse- 
serum.  In  such  persons,  who  are  frequently  asthmatics, 
the  administration  of  antitoxin  may  give  rise  to  severe 
asthmatic  paroxysms,  cardiac  weakness,  suspension  of 
respiration,  and  even  death.  It  is  a  remarkable  thing 
that  most  of  such  people  are  frequently  thrown  into 
asthmatic  paroxysms  by  the  presence  of  a  horse  or  the 
odors  of  horses. 

Bacillus  Typhosus  (Bacillus  of  Eberth). — A  ^Bl-motile, 
facultative  anaerobic  bacterium.  There  is  practically 
but  one  source  of  infection,  the  feces  or  urine  of  a  typhoid 
patient,  and  one  avenue  of  infection,  the  digestive  tract, 
so  that  to  have  typhoid  fever  one  must  virtually  eat 
some  one's  excreta,  no  matter  with  what  dish  it  may  be 
served.  A  contaminated  water-supply  is  the  greatest 
agent  of  infection. 


PATHOGENIC  BACTERIA  AND  DISEASES  49 

Next  to  water,  milk  is  the  most  frequent  carrier  of  the 
infective  germ.  Raw  oysters  and  uncooked  vegetables 
may  convey  the  infection.  The  pernicious  practice  of 
fattening  oysters  on  sewage  has  been  the  cause  of  untold 
deaths  of  typhoid  fever  in  the  past.  Flies  frequently 
carry  the  infection  from  out-houses  to  foods  of  various 
kinds.  The  site  of  infection  is  the  Peyer's  patches  of 
the  small  intestine,  though  the  germ  is  found  in  the  blood, 
milk,  spleen,  liver,  and  lymphatic  glands,  and  it  is 
thought  it  may  gain  entrance  through  the  tonsils. 
Locally,  there  may  be  ulceration  of  the  intestines,  which 
ofttimes  leads  to  hemorrhage  and  even  perforation. 
The  symptoms  of  the  disease  are  those  of  a  continued 
toxemia,  fever,  exhaustion,  and  delirium. 

Typhoid  Carriers. — Cultures  of  bacteria  may  remain  in 
the  gall-bladder  or  other  organs  for  months  or  even  years, 
the  individual  suffering  no  inconvenience,  and  thus 
becoming  a  walking  source  of  infection  for  others. 

Widal  Test. — When  the  blood  of  a  person  suffering 
from  typhoid  fever  is  mixed  with  a  living  culture  of 
typhoid  bacteria  and  examined  in  the  hanging  drop  with 
the  microscope,  the  bacteria  are  seen  to  clump  together 
and  cease  their  movements.  This  is  due  to  the  agglutin- 
ating property  of  the  blood  in  this  infection,  spoken  of 
elsewhere. 

Drying  of  the  blood  and  considerable  dilution  does  not 
interfere  with  its  accuracy,  so  that  in  practice  a  drop  of 

blood  is  drawn  on  to  a  piece  of  filter-paper  and  sent  to 

4  "' 


50  BACTERIOLOGY 

the  laboratory,  where  it  is  soaked  out  with  water  and 
added  to  the  culture. 

Prevention  of  Infection. — A  vaccine  has  been  prepared 
from  dead  cultures  of  the  bacillus  which  raises  the 
opsonic  index  for  this  germ,  and  gives  so  high  a  degree  of 
immunity  that  it  is  coming  into  universal  use. 

The  best  means  of  combating  the  spread  of  the  in- 
fection is  absolute  sterilization  of  all  excreta  from  ty- 
phoid patients  by  thoroughly  mixing  with  formaldehyd 
and  allowing  to  stand  for  several  hours,  stirring  in  the 
meantime.  Pure  water-  and  milk-supply  or  steriliza- 
tion of  same.  Extermination  of  flies  and  vaccination. 


CHAPTER  VIII 

PATHOGENIC    BACTERIA   AND    DISEASES   CAUSED   BY 
THEM  (Continued) 

Bacillus  of  Tetanus. — A  slightly  motile,  spore-forming 
anaerobic  bacterium. 

Sources  of  Infection. — The  germ  is  widely  distributed, 
occurring  in  garden  earth  and  the  feces  of  herbivorous 
animals. 

The  avenue  of  infection  is  practically  always  a  wound, 
and  usually,  because  of  the  anaerobic  nature  of  the  germ, 
a  punctured  wound.  Fourth  of  July  injuries,  in  which 
pieces  of  wad  and  paper  are  blown  into  the  hand,  are 
prolific  sources  of  tetanus  infection. 

Lesions. — The  site  of  infection  causes  but  little  trouble, 
as  this  is  an  example  of  a  purely  toxic  disease.  The  toxin, 
which  is  very  virulent,  is  absorbed  and  acts  upon  the 
cells  of  the  central  nervous  system  in  a  manner  resem- 
bling strychnin,  causing  convulsions  and  opisthotonos. 
To  stand  helplessly  by  and  watch  the  agonizing  struggles 
and  convulsions  of  a  patient  afflicted  with  tetanus,  and 
listen  to  his  pleading  for  relief,  is  one  of  the  most  heart- 
rending experiences  a  nurse  may  be  called  upon  to 
endure. 

Antitoxin. — An  antitoxin  is  prepared  from  the  horse 
in  the  usual  manner,  but  to  be  of  value  it  must  be  given 

51 


52  BACTERIOLOGY 

very  early  indeed,  as  the  fatal  dose  of  the  toxin  is  so 
infinitesimal.  Its  greatest  value  is  as  a  prophylactic 
measure  in  cases  of  suspected  infection.  If  given  at  the 
time  of  infection  it  is  an  absolute  preventive. 

Preventive  measures  include  the  exposure  to  air  of 
all  punctured  wounds,  opening  them  to  admit  air  to  all 
parts,  and  the  immediate  injection  of  antitoxin  in  all 
cases  of  suspected  infection,  as  blank-cartridge  wounds, 
nail  wounds,  and  all  punctured  wounds  caused  by  blunt 
instruments  that  are  contaminated  with  soil  or  manure. 

Bacillus  of  Influenza  (Bacillus  of  Pfeiffer). — A  non- 
spore-forming,  non-motile  aerobic  bacterium  found  in 
the  sputum,  bronchial  and  nasal  secretions  of  those 
suffering  from  the  disease.  It  has  never  been  discovered 
outside  the  body,  and  probably  is  always  transmitted 
from  patient  to  patient.  It  produces  catarrhal  inflam- 
mation of  the  respiratory  mucous  membranes  with  con- 
stitutional symptoms  of  fever,  depression,  exhaustion, 
etc.,  indicating  the  presence  of  a  toxin,  though  it  has 
not  yet  been  demonstrated. 

Bacillus  Anthracis. — A  non-motile,  aerobic,  spore-form- 
ing bacterium.  Its  spores  are  the  most  resistant  of  any 
known  germ,  having  been  known  to  withstand  boiling 
for  half  an  hour,  5  per  cent,  carbolic  acid  solution  for 
forty  days,  and  i :  1000  bichlorid  solution  for  three  days. 
Because  of  this  great  resistance  it  is  used  as  a  standard 
for  determining  the  potency  of  various  germicides  and 
antiseptics. 


PATHOGENIC  BACTERIA  AND  DISEASES  53 

It  is  the  cause  of  anthrax,  a  disease  more  particularly 
of  cattle  and  sheep,  man  only  acquiring  it  from  contact 
with  these  animals  or  their  products.  Woolsorters' 
disease  is  anthrax  of  the  lungs  in  man.  It  occurs  in 
those  who  handle  wool  from  sheep  which  have  been 
affected.  Infection  usually  occurs  through  wounds  of 
the  skin,  where  it  produces  a  localized  inflammation 
termed  malignant  pustule. 

Animals  are  rendered  immune  to  disease  by  vaccina- 
tion with  attenuated  cultures  of  the  germ.  There  is 
some  risk  attached  to  this  method,  and  it  is  never  em- 
ployed in  man. 

Bacillus  Mallei  (Bacillus  of  Glanders). — A  facultative 
anaerobic,  non-spore-forming  bacterium,  the  cause  of 
glanders.  Like  anthrax,  glanders  is  a  disease  of  the 
lower  animals  more  particularly,  man  acquiring  it  by 
contact  with  such  animals. 

The  source  of  infection  is  the  discharge  from  the  le- 
sions of  the  disease,  and  the  site  of  infection  is  the  nasal 
mucous  membrane  or  wounds  of  the  skin.  Nodules 
of  the  skin  and  mucous  membranes  occur  and  break 
down,  forming  ulcers.  The  neighboring  lymph-glands 
become  swollen  and  a  profuse  discharge  occurs,  which 
is  highly  infective. 

Mallein,  a  product  similar  to  tuberculin,  is  used  as  a 
diagnostic  measure  in  animals.  A  reaction  similar  to 
that  following  the  use  of  tuberculin  follows  its  use  in 
affected  animals.  Prevention  consists  of  prompt  kill- 


54  BACTERIOLOGY 

ing  of  affected  animals,  and  proper  disinfection  of  their 
quarters. 

Bacillus  Leprse  (Bacillus  of  Leprosy). — A  non-motile 
bacillus.  Spores  have  not  as  yet  been  demonstrated. 
Sources  of  infection  have  not  yet  been  determined. 
Lesions  are  thickening  and  nodules  of  granulation  tissue 
in  the  skin  and  peripheral  nerves,  though  other  tissues 
and  the  internal  organs  may  be  affected.  It  is  un- 
certain whether  the  disease  may  be  transmitted  from 
one  person  to  another  or  not. 

Leprolin. — This  is  a  substance  analogous  to  tuberculin, 
and  is  prepared  from  cultures  of  lepra  bacilli.  It  is 
used  as  a  diagnostic  measure  and  has  shown  little  or 
no  curative  properties. 

Bacillus  of  Bubonic  Plague. — A  facultative  anaerobic, 
non-motile,  non-spore-forming  bacillus,  the  cause  of 
bubonic  plague. 

Source  of  Infection. — Fleas  carry  the  infection  from 
rats  to  man  and  other  animals,  particularly  ground 
squirrels.  Direct  infection  from  dust  or  air  seldom  if 
ever  occurs.  Infection  doubtless  always  occurs  through 
the  skin  by  the  bite  of  a  flea  or  fly,  usually  the  rat 
flea. 

No  local  reaction  occurs  at  the  site  of  infection,  but 
inflammation  of  the  neighboring  lymphatic  glands  soon 
follows. 

Three  forms  of  the  disease  are  recognized:  bubonic, 
distinguished  by  enlargement  and  suppuration  of  the 


PATHOGENIC  BACTERIA  AND  DISEASES  55 

lymphatic  gland  (buboes);  pulmonic,  where  the  lungs 
bear  the  brunt  of  the  attack;  septicemic,  a  generalized 
form  of  the  disease. 

Preventive  Measures. — Destruction  of  rats  and  their 
fleas.  The  rat  flea  normally  does  not  attack  man,  but 
when  the  rats  die  and  become  cold  the  fleas  leave  the 
bodies  and  seek  warmth  and  nourishment  wherever 
they  may  be  found.  It  is  thus  that  they  are  forced  to 
seek  sustenance  upon  an  abnormal  host. 

Vaccines  have  been  used  with  some  success  in  estab- 
lishing immunity  to  the  disease;  an  antitoxin  is  also 
being  used  with  encouraging  results  in  the  treatment. 

SPIRILLA 

Spirillum  Choleras  Asiaticae  (Comma  Bacillus  of 
Cholera). — An  aerobic,  motile,  non-spore-forming  bac- 
terium of  the  spirilla  class.  It  is  the  cause  of  Asiatic 
cholera,  one  of  the  most  dreaded  diseases  of  ancient 
and  modern  times. 

The  source  of  infection  is  usually  drinking-water;  less 
frequently,  food  or  other  ingested  material. 

The  avenue  of  infection  is  always  the  intestinal  canal. 
Like  typhoid  fever,  cholera  is  always  a  filth  disease.  To 
be  infected  one  must  always  swallow  the  excreta  of  some 
1  one  having  the  disease.  Flies  act  as  carriers,  as  in  ty- 
phoid. 

Lesions  are  localized  in  the  intestinal  canal  and  the 
spirilla  are  not  found  in  the  blood.  It  is  essentially  a 


56  BACTERIOLOGY 

toxic  disease,  as  injection  of  the  toxins  produce  typic 
symptoms  of  the  disease. 

Symptoms  are  diarrhea,  fever,  prostration,  and 
clammy  skin,  etc. 

The  agglutination  test,  as  in  typhoid,  is  positive. 

Protective  vaccines  have  been  used  with  considerable 
success,  but  efforts  to  produce  an  antitoxin  have  been 
unsuccessful. 

Treponema  Pallidum  (Spironema  Pallida). — A  minute 
spiral-shaped  motile  organism,  found  in  chancre,  lym- 
phatic glands,  and  in  secondary  lesions,  mucous  patches, 
ulcers,  and  all  organs  in  hereditary  syphilis. 

The  source  of  infection  is  the  discharge  from  the  prim- 
ary lesion  or  chancre,  the  secondary  lesions,  or  suppura- 
tive  lesions  of  the  tertiary  stage.  The  organism  evi- 
dently enters  the  blood  at  once,  as  removal  of  the 
chancre  or  site  of  primary  infection  at  the  earliest  pos- 
sible moment  fails  to  prevent  the  disease. 

Means  of  infection  is  usually  through  sexual  inter- 
course by  introduction  of  the  germ  through  minute 
abrasions  of  the  skin  or  mucous  membrane  of  the  genital 
organs.  It  is  acquired  innocently,  especially  by  nurses 
and  physicians,  or  any  one  coming  in  contact  with  the 
discharges  of  syphilitic  sores. 

Prevention  consists  in  avoidance  of  such  sources  of 
infections,  both  sexually  and  otherwise,  and  strict  anti- 
septic precautions  or  rubber  gloves  in  handling  syphilitic 
patients.  The  only  animal  known  to  be  susceptible 


PATHOGENIC  BACTERIA  AND  DISEASES  57 

to  syphilis  is  the  anthropoid  ape,  so  that  infection  is 
always  from  individual  to  individual  or  is  inherited, 
that  is,  from  mother  to  child,  or  father  to  child. 

Spirillum  of  Relapsing  Fever. — A  motile  spirillum 
with  flagella,  the  cause  of  a  recurrent  or  intermittent 
fever.  It  is  found  in  the  blood  of  patients  suffering  from 
the  disease,  but  only  during  the  period  of  fever.  After 
the  attack  the  spirilla  congregate  in  the  spleen  and  finally 
die  there. 

The  agglutination  test  is  positive.  The  germ  is  path- 
ogenic to  man  and  monkeys,  and  is  transmitted  by  the 
bite  of  the  bed-bug. 


CHAPTER  IX 
PROTOZOA  AND  DISEASES  CAUSED  BY  PROTOZOA 

Plasmodium  Malarias. — There  are  three  species  of 
this  parasite,  each  giving  rise  to  a  different  type  of 
malarial  fever: 

The  tertian  variety,  in  which  the  parasite  reaches 
maturity  in  forty-eight  hours,  and  causes  the  benign 
tertian  type  of  the  disease. 

The  quartan  variety,  which  reaches  maturity  in  seventy- 
two  hours,  and  causes  the  benign  quartan  type  of  the 
disease. 

The  estivo-autumnal  variety,  developing  to  maturity 
in  twenty-four  to  forty-eight  hours,  and  causing  the 
malignant  estivo-autumnal  type  of  the  disease. 

The  source  of  infection  is  the  bite  of  the  mosquito,  in 
whom  the  sexual  cycle  of  development  of  the  parasite 
occurs.  The  mosquito  can  only  become  infected  by 
sucking  the  blood  of  a  malarial  patient. 

Amoeba  Dysenteriae. — A  protozoon  the  cause  of 
amebic  dysentery.  Found  in  the  intestinal  ulcers, 
feces,  and  secondary  liver  abscesses  of  those  suffering 
from  the  disease.  Source  of  infection  is  unknown. 

58 


PROTOZOA  AND  DISEASES  CAUSED  BY  PROTOZOA     59 

Trypanosomata. — Trypanosomes  are  flagellated  motile 
protozoa.  Various  varieties  occur,  causing  numerous 
diseases  of  animals.  One  variety  causes  the  peculiar 
sleeping-sickness  of  Africa,  the  tsetse-fly  being  the  means 
of  infection. 


CHAPTER  X 

% 

ANTISEPTICS,  DISINFECTANTS,  AND  GERMICIDES 

Germicide. — An  agent  capable  of  killing  bacteria. 

Disinfectant. — Also  an  agent  capable  of  killing  bac- 
teria. The  term,  however,  is  usually  restricted  to  such 
germicides  as  are  used  to  disinfect  rooms,  buildings,  cars, 
and  similar  structures. 

Antiseptic. — A  substance  capable  of  preventing  the 
growth  and  development  of  germs,  but  not  necessarily 
destroying  them.  A  disinfectant  or  germicide  is  nec- 
essarily an  antiseptic,  but  an  antiseptic  is  neither  a 
germicide  nor  disinfectant.  A  disinfectant  is  the  term 
used  in  speaking  of  a  germicide  used  for  destroying  the 
contagion  after  contagious  disease,  to  disinfect  discharges, 
excreta,  clothing  in  infectious  diseases,  and  to  prepare 
the  hands,  the  field  of  operation,  and  room  in  which  an 
operation  is  to  be  performed.  An  antiseptic  is  used  for 
the  purpose  of  keeping  wound  dressings  aseptic,  or  to 
assist  nature  in  conquering  infection  after  it  has  occurred. 
Most  disinfectants  or  germicides  in  germicidal  strength 
are  too  strong  for  use  in  wounds,  as  they  may  destroy 
the  tissue  cells  as  well  as  the  bacteria. 

Deodorants  are  substances  which  destroy  odors. 
While  germicides  may  do  this,  the  term  is  usually  re- 

60 


ANTISEPTICS,  DISINFECTANTS,  AND  GERMICIDES     61 

stricted  to  substances  which  without  germicidal  action 
simply  disguise  or  destroy  odors. 

Sterilization  is  the  destruction  of  bacteria  and  their 
spores  by  heat  or  other  means. 

Heat. — Where  applicable,  heat  is  the  most  efficient 
disinfectant  we  have.  There  are,  however,  many  things 
which  cannot  be  subjected  to  boiling,  high  dry  heat,  or 
the  open  flame. 

Steam  is  the  most  general  means  of  employing  heat. 
Surgical  dressings,  cotton,  gauze,  bandages,  gowns, 
caps,  face-masks,  etc.,  are  best  sterilized  by  means  of 
steam  in  a  properly  constructed  apparatus  or  sterilizer. 

Superheated  steam  (i.  e.,  steam  underpressure)  is  more 
efficient  and  more  rapid  in  action,  but  the  ordinary 
sterilizer  does  not  take  advantage  of  this  principle,  and 
more  time  must,  therefore,  be  allowed  than  in  the  press- 
ure apparatus.  One  hour  is  considered  sufficient  for 
the  sterilization  of  ordinary  dressings,  gowns,  etc.,  with 
the  low-pressure  sterilizer,  while  half  that  time  is  suffi- 
cient with  the  high-pressure  apparatus. 

DISINFECTANTS  AND  ANTISEPTICS 

Mercuric  Chlorid. — Bichlorid  of  mercury  is  a  corrosive 
poison,  usually  supplied  in  tablets  which  are  colored 
blue.  It  is  probably  the  most  used  of  all  germicides. 
It  is  used  in  solutions  of  i :  1000  to  i :  5000  strength. 
Its  most  useful  field  is  in  the  disinfection  of  hands,  the 
site  of  operation,  and  elsewhere  on  the  unbroken  skin. 


62  BACTERIOLOGY 

Because  of  its  toxic  properties  it  is  unsafe  for  use  in  irri- 
gation of  cavities,  and  because  of  its  irritating  and  corro- 
sive action  unsuited  for  wound  dressing.  By  coagulat- 
ing the  albumin  of  the  wound  discharges  it  defeats 
its  purpose  as  an  antiseptic  and  is  extremely  painful 
besides. 

Mercuric  lodid. — This  is  a  germicide  of  much  power, 
and  because  of  its  not  coagulating  albumin  is  of  greater 
value  in  some  conditions  than  the  bichlorid.  It  is  com- 
bined with  potassium  in  the  form  of  a  soap,  which  makes 
an  ideal  hand  disinfectant. 

Silver  Nitrate. — This  is  a  caustic  poison  of  high  ger- 
micidal  value,  but  owing  to  the  unstable  property  of  its 
solutions,  the  silver  being  precipitated  by  chlorids  or 
inorganic  salts,  it  is  of  little  clinical  value.  Its  most 
important  use  is  in  Crede*'s  method  for  the  prevention 
of  gonorrheal  infection  of  the  eyes  of  the  newborn,  where 
a  2  per  cent,  solution  is  instilled  into  the  eyes  and  im- 
mediately neutralized  with  normal  salt  solution. 

Carbolic  Acid. — A  poison  of  high  germicidal  value 
extensively  used,  especially  in  domestic  practice.  It  is 
used  in  from  i  to  5  per  cent,  solution,  and  finds  its  great- 
est field  of  usefulness  as  an  all-round  antiseptic  in  the 
treatment  of  infected  wounds. 

Gangrene  of  the  fingers  and  toes  has  followed  its 
prolonged  use  as  a  wet  dressing.  Caution  should, 
therefore,  be  used  in  its  application  on  dressings,  band- 
ages, etc, 


ANTISEPTICS,  DISINFECTANTS,  AND  GERMICIDES     63 

Lysol. — This  is  a  coal-tar  product  closely  related 
to  carbolic  acid,  but  far  less  poisonous.  It  is  largely 
supplanting  the  latter  for  hand  disinfection  and  in 
obstetric  practice.  It  is  used  in  i  to  5  per  cent,  solu- 
tion. 

lodin. — This  is  one  of  the  most  efficient  germicides  we 
possess.  In  the  form  of  the  tincture  it  is  used  to  cauter- 
ize corneal  ulcers  and  as  an  application  to  indolent  ulcers 
and  suppurating  surfaces.  A  i :  1000  solution  in  water  is 
used  for  hand  disinfection.  It  has  the  disadvantage  of 
staining  the  hands,  which  must  be  decolorized  with 
solution  of  ammonia.  It  is  coming  into  frequent  use  on 
the  Continent  for  preparing  the  field  of  operation,  the 
skin  being  simply  swabbed  with  the  tincture  and  all 
scrubbing  dispensed  with. 

Its  greatest  use  is  in  the  preparation  of  catgut  liga- 
tures, which  it  not  only  renders  sterile,  but  antiseptic, 
thus  tending  to  prevent  stitch  abscess. 

Potassium  Permanganate. — This  is  a  germicide  for- 
merly much  used  in  hand  disinfection.  It  stains  the 
skin  a  mahogany  brown,  and  it  is  necessary  to  follow 
its  use  with  a  solution  of  oxalic  acid  to  remove  the  stain. 
Its  use  now  is  restricted  mostly  to  the  treatment  of 
gonorrhea. 

Formalin  is  a  40  per  cent,  solution  of  formaldehyd 
gas.  It  is  a  powerful  germicide,  and  owing  to  its  gas- 
eous nature  is  the  best  disinfectant  we  possess  for  fumi- 
gating rooms,  dwellings,  cars,  etc.,  after  contagious  dis- 


64  BACTERIOLOGY 

ease.  It  is  harmless  to  colors,  metals,  clothing,  etc., 
but  because  of  its  highly  irritating  character  it  is  prac- 
tically useless  for  purposes  where  it  would  come  in  con- 
tact with  the  human  tissues,  as  in  hand  disinfection, 
wound  dressing,  etc.  It  is  used  to  sterilize  eye  and  ear 
instruments  whose  delicate  edges  forbid  their  being 
boiled.  The  formalin  is  vaporized  in  a  closed  space 
where  the  instruments  are  placed.  For  fumigating 
rooms  after  contagious  diseases  the  vaporization  of  the 
formaldehyd  gas  is  accomplished  by  adding  to  the  for- 
malin potassium  permanganate  in  the  proportion  of 
8  ounces  of  potassium  permanganate  to  16  ounces  of 
formalin  for  each  1000  cubic  feet  to  be  fumigated. 

When  the  two  drugs  are  mixed  a  rapid  effervescence 
takes  place,  with  the  production  of  considerable  heat, 
whereby  the  gas  is  vaporized.  The  vessel  containing 
the  mixture  should  be  placed  within  another  containing 
water,  as  the  heat  may  be  sufficient  to  ignite  wood  or 
other  inflammable  substances  with  which  it  comes  in 
contact.  Bedding,  clothing,  etc.,  should  be  spread  out, 
and  drawers  and  boxes  opened  to  allow  the  gas  to  gain 
access  to  them.  All  doors,  windows,  or  other  openings 
should  be  closed  and  paper  or  adhesive  plaster  pasted 
over  all  cracks  or  crevices  where  the  gas  might  escape. 
The  gas  should  be  allowed  to  remain  in  the  room  for 
at  least  ten  hours. 

Acetozone. — This  is  a  new  non-poisonous  germicide 
of  great  value.  It  is  of  value  only  in  solutions,  and  as 


ANTISEPTICS,  DISINFECTANTS,  AND  GERMICIDES     65 

such  solutions  are  very  unstable  they  must  be  prepared 
as  needed.  It  is  used  in  solutions  of  i :  1000,  and  be- 
cause of  its  non-toxic  character  may  be  used  with  im- 
punity about  the  nose,  mouth,  and  throat,  where  more 
poisonous  germicides  may  not  be  used.  It  is  used  in- 
ternally as  an  intestinal  antiseptic,  but  owing  to  its 
unstable  character  it  is  doubtful  if  it  ever  passes  the 
stomach  and  reaches  the  intestines  in  its  original  form. 
It  may  be  used  with  satisfaction  for  colonic  flushing  in 
dysentery  and  colitis. 

Turpentine. — This  is  a  germicide  of  some  value,  but 
of  limited  use.  The  late  Nicholas  Senn  was  wont  to 
resort  to  its  use  very  frequently,  especially  before  opera- 
tions that  involved  the  opening  of  the  synovial  sacs  of 
joints.  Its  addition  to  the  ordinary  green  soap  used  in 
hand  disinfection  materially  increases  the  usefulness  of 
the  latter. 

Alcohol  is  a  disinfectant  used  principally  in  hand 
disinfection,  where,  because  of  its  solvent  action  on  the 
fatty  matter  of  the  skin,  it  is  of  peculiar  value.  It 
thus  brings  the  germs  out  of  the  pores  to  the  surface, 
where  they  may  be  destroyed  by  it  and  other  germicides. 
It  is  also  much  used  for  the  preservation  of  pathologic 
specimens. 

Hydrogen  Peroxid. — This  is  a  liquid  which  depends 
upon  the  oxygen  in  its  composition  for  its  antiseptic 
virtue.  It  is  not  of  great  antiseptic  value,  but  owing  to 
its  property  of  decomposing  pus  it  is  much  used  for 

5 


66  BACTERIOLOGY 

cleansing  suppurating  wounds  and  loosening  dressings 
which  have  become  adherent  from  dried  secretions.  It 
should  never  be  used  in  suppurating  cavities  where  there 
is  not  a  free  outlet  for  the  gas  which  is  formed  by  its 
decomposition,  as  the  pressure  might  force  septic  mate- 
rial out  into  healthy  tissue. 

lodoform. — This  is  a  yellow  powder  of  high  iodin  con- 
tent. It  was  formerly  much  used  as  an  antiseptic  in 
dry  dressings.  It  is  in  itself  not  antiseptic,  and  should 
be  sterilized  before  use  on  a  sterile  wound,  but  in  con- 
tact with  pus  it  is  decomposed,  giving  off  free  iodin, 
which  in  turn  acts  as  an  antiseptic.  Because  of  its 
particularly  obnoxious  odor  and  slight  germicidal  value 
it  is  rapidly  falling  into  disuse. 

Aristol  (Thymol  lodid). — This  is  a  reddish-brown 
powder  containing  45  per  cent,  iodin.  It  has  almost 
supplanted  iodoform  as  a  dry  dressing,  being  free  from 
its  disagreeable  odor  and  less  toxic. 

Formidin. — This  is  a  reddish  powder  containing 
formaldehyd,  salicylic  acid,  and  iodin  in  combination. 
It  is  of  greater  value  than  either  of  the  last-named  drugs. 
Being  non-irritant  and  practically  non-toxic,  it  may  be 
used  both  internally  and  externally  without  danger. 
In  the  presence  of  wound  secretions,  pus,  or  the  intestinal 
secretions  it  breaks  up  into  its  component  parts — iodin, 
formaldehyd,  and  salicylic  acid — all  of  which  are  anti- 
septics. It  is  used  as  a  dressing  powder  and  for  the 
preparation  of  antiseptic  gauze. 


ANTISEPTICS,  DISINFECTANTS,  AND  GERMICIDES      67 

Bismuth  Subnitrate. — This  is  a  white  powder  of  very 
little  antiseptic  value.  It  has  recently  sprung  into 
prominence  for  the  treatment  of  tuberculous  cavities  of 
bone  and  suppurating  disease  of  the  accessory  sinuses  of 
the  nose.  It  is  used  in  the  form  of  a  paste  combined 
with  bismuth,  iodid,  and  petrolatum. 


CHAPTER  XI 
SUSCEPTIBILITY  AND  INFECTION 

SUSCEPTIBILITY,  as  we  have  learned,  is  that  condi- 
tion of  the  animal  organism  which  permits  of  the  growth 
and  development  in  its  tissues  of  a  disease  germ  with  the 
production  of  the  characteristic  symptoms  and  lesions 
of  the  disease  of  which  it  is  the  cause. 

It  is  the  opposite  of  immunity.  Varying  conditions 
and  circumstances  produce  varying  degrees  of  suscepti- 
bility. No  germ  is  capable  of  producing  disease  in  all 
animals  under  all  conditions. 

Age  is  often  an  element  in  susceptibility,  the  young  of 
all  animals  being  generally  more  susceptible  to  infection 
than  the  adult.  The  increased  susceptibility  of  children 
to  measles,  scarlet  fever,  and  whooping-cough  is  well 
known.  Certain  germs  are  capable  of  producing  disease 
in  some  animals  and  incapable  of  producing  it  in  others. 
Frequently  the  susceptibility  of  the  host  depends  upon 
the  virulence  of  the  germ.  Likewise,  the  severity  of  the 
disturbance  produced  depends  largely  upon  the  virulence 
of  the  infecting  germ,  as  well  as  upon  the  resistance 
or  susceptibility  of  the  host.  Again,  the  degree  of  sus- 
ceptibility depends  upon  the  number  of  germs  which 


SUSCEPTIBILITY  AND  INFECTION  69 

gain  entrance  into  the  body  of  the  host.  A  few  virulent 
germs  may  succeed  in  establishing  an  infection  where  a 
larger  number  of  attenuated  ones  might  fail. 

The  route  by  which  the  germ  gains  entrance  to  the 
body  has  also  an  influence  upon  the  susceptibility  of  the 
animal  to  infection,  intravenous  injection  of  germs  pro- 
ducing infection  where  subcutaneous  injections  fail. 
Certain  germs  have  certain  routes  of  entrance  to  the 
body,  and  entrance  by  any  other  route  reduces  the 
chances  of  infection  or  reduces  the  intensity  of  the  pro- 
cess when  infection  occurs.  The  resistance  to  cholera 
infection  is  greater  in  subcutaneous  infection  than  when 
infection  occurs  by  way  of  the  intestinal  canal,  the 
usual  route.  Lowered  vitality  from  an  attack  of  one 
disease  often  increases  the  susceptibility  to  another  in- 
fection, as  in  the  susceptibility  to  tuberculosis  following 
measles. 

Fatigue  is,  without  doubt,  responsible  for  a  great  deal 
of  increased  susceptibility.  White  rats,  which  are  im- 
mune to  anthrax,  become  susceptible  when  fatigued. 
Starvation  also  reduces  the  resistance.  Pigeons,  which 
are  immune  to  anthrax,  become  susceptible  upon  starv- 
ing. Heat,  cold,  and  moisture  also  increase  the  chance 
of  infection,  as  was  shown  by  Pasteur,  who,  by  immers- 
ing a  hen  in  water,  made  her  susceptible  to  anthrax,  to 
which  chickens  are  normally  immune.  Improper  food 
and  drugs  may  increase  the  chances  of  infection.  Han- 
kin  fed  immune  rats  on  sour  milk  and  bread  and  made 


70  BACTERIOLOGY 

them  susceptible.  Inhalation  of  ether  increases  the  sus- 
ceptibility to  pneumococcic  infection. 

Injury  and  perverted  function  also  increase  the  sus- 
ceptibility to  infection.  Thus,  tuberculosis  of  the  joints 
and  bones  frequently  follows  traumatic  injury,  while 
diminution  of  the  acidity  of  the  gastric  juice  increases 
the  susceptibility  to  cholera  infection.  Infection  coin- 
cidently  of  saprophytic  germs  with  tetanus  bacillus  in- 
creases the  chances  of  tetanus  infection. 

In  some  infections,  as  pneumonia,  the  susceptibility 
is  increased  by  a  previous  attack  of  the  disease,  while  in 
others  immunity  is  conferred  by  an  attack,  as  in  small- 
pox, or  decreased  susceptibility  occurs  without  producing 
complete  immunity,  as  in  diphtheria. 

The  coverings  of  the  external  surface  of  the  organism, 
the  skin,  and  mucous  membranes  present  certain  obsta- 
cles to  infection.  Many  conditions  arise  to  destroy  the 
integrity  of  these  coverings  and  thus  increases  the  sus- 
ceptibility to  infection. 

The  unbroken  skin  is  practically  impervious  to  germs, 
though  they  doubtless  do  obtain  entrance  occasionally 
by  way  of  the  hair-follicles  and  the  ducts  of  the  sweat- 
glands.  Scratches,  minute  abrasions,  and  other  breaches 
of  continuity  let  down  the  bars  for  the  entrance  of  germs, 
though  they  are  often  destroyed  by  phagocytosis  im- 
mediately upon  their  entrance. 

The  mucous  membranes  of  the  mouth,  throat,  and 
nasal  cavities  normally  present  considerable  resistance 


SUSCEPTIBILITY  AND  INFECTION  71 

to  infection,  as  is  shown  by  the  frequent  presence  upon 
them  of  virulent  germs,  as  the  diphtheria  and  influenza 
bacillus  and  the  streptococcus  in  persons  in  perfect  health. 
The  constant  flow  of  mucus  and  the  movement  of  the 
ciliated  epithelium  tend  to  prevent  the  entrance  of  the 
germs  through  these  surfaces,  but  injury,  excessive  dry- 
ing of  the  surfaces  from  overheated  rooms,  and  disease 
may  lower  the  resistance  offered  by  these  surfaces  and 
increase  the  liability  to  infection. 

Few  bacteria  reach  the  lungs,  but  those  that  do  are 
quickly  taken  up  by  the  fixed  epithelial  cells  and  the 
leukocytes.  Under  certain  unfavorable  conditions  this 
does  not  occur,  and  infection  occurs  through  the  lungs. 
The  stomach  is  exceptionally  free  from  infection.  This 
is  doubtless  due  to  the  fact  that  the  gastric  juice  is  detri- 
mental to  bacterial  activity.  It  is  not  germicidal,  how- 
ever, and  therefore  does  not  prevent  the  entrance  into 
the  intestines  of  bacteria,  which  may  there  cause 
trouble. 

The  intestines  present  a  feeble  resistance  to  bacterial 
activity  in  the  bile,  but,  on  the  whole,  bacteria  do  fairly 
well  in  the  intestinal  contents.  The  intestinal  walls 
normally,  however,  present  considerable  resistance  to  the 
entrance  of  germs,  as  is  evidenced  by  the  large  number 
of  bacteria  found  in  the  intestinal  contents  of  healthy 
individuals,  even  typhoid  bacilli  and  cholera  germs  hav- 
ing been  found  in  the  bowel  movements  of  healthy 
persons.  Certain  conditions,  as  improper  feeding, 


72  BACTERIOLOGY 

heat,  depression,  and  other  unknown  influences,  increase 
the  susceptibility  to  intestinal  infection. 

TRANSMISSION  OF  INFECTION 

With  the  exception  of  the  tetanus  bacillus,  which  lives 
naturally  upon  the  soil  and  the  intestinal  contents  of 
horses,  most  pathogenic  bacteria  can  exist  but  a  short 
time  outside  the  animal  body.  Transmission  of  infec- 
tion usually  occurs  by  direct  contact  with  an  individ- 
ual having  the  disease  or  with  a  secretion  from  his 
body. 

The  gonococcus  dies  very  soon  outside  the  body,  the 
pneumococcus  is  longer  lived,  and  the  typhoid  bacillus 
and  tubercle  bacillus  can  exist  for  a  considerable  length 
of  time  outside  the  body.  The  diphtheria  bacillus  and 
typhoid  germ  even  grow  and  develop  in  milk.  Not  a  few 
epidemics  have  been  traced  to  this  source.  Recent  in- 
vestigations tend  to  show  that  the  germ  carrier  is  re- 
sponsible for  the  transmission  of  many  cases  of  infection. 

Carriers  are  individuals  who  after  recovery  from  disease 
continue  to  throw  off  virulent  germs  for  long  periods  of 
time,  or  others  who,  after  contact  with  infected  persons, 
carry  the  germs  in  their  nose,  throat,  or  intestines,  though 
themselves  healthy.  Among  the  diseases  thus  trans- 
mitted are  typhoid  fever,  cholera,  influenza,  pneumonia, 
and  diphtheria. 

Germs  which  leave  the  body  with  intestinal  excretions, 
as  in  typhoid  and  cholera,  are  likely  to  contaminate  a 


SUSCEPTIBILITY  AND  INFECTION  73 

water-supply  and  thus  be  transmitted  to  others,  or  to 
contaminate  the  feet  of  flies,  which,  in  turn,  infect  some 
food.  Those  which  leave  the  individual  in  the  exhaled 
air,  as  tubercle  bacilli,  pneumococcus,  or  diphtheria 
germs,  are  likely  to  be  inhaled  or  ingested  with  food,  or 
they  may  infect  eating  or  drinking  utensils. 

Certain  insects  may  be  the  means  of  transmitting  in- 
fection. The  fly  may  carry  typhoid,  cholera,  tubercu- 
losis; the  flea  transmits  the  plague;  the  mosquito, 
malaria  and  yellow  fever;  the  tsetse-fly,  sleeping-sick- 
ness. 

PREVENTION  OF  INFECTION 

GENERAL  PRECAUTIONS  FOR  NURSES 

The  nurse  in  charge  of  a  case  of  infectious  or  contagious 
disease  owes  a  duty  not  only  to  the  patient,  but  to  her- 
self, to  the  family,  and  to  the  public.  She  should  use 
every  care  to  protect  herself  from  infection,  that  her 
usefulness  to  the  patient,  the  family,  and  to  the  public 
may  not  be  curtailed  or  destroyed.  She  should,  there- 
fore, avail  herself  of  every  protection  possible  before 
entering  upon  the  case. 

In  the  first  place,  she  should  be  in  perfect  health. 
Any  nurse  who  expects  to  nurse  typhoid  fever  should 
have  been  vaccinated  against  the  infection  long  enough 
before  going  on  a  case  for  immunity  to  have  been  estab- 
lished. In  diphtheria  she  should  have  had  an  immuniz- 
ing dose  of  antitoxin.  She  should  be  scrupulously 


74  BACTERIOLOGY 

clean  as  to  her  hands,  nails,  teeth,  and  hair,  and  should 
not  eat  or  drink  in  the  sick  room. 

She  should  not  lower  her  vitality  by  overwork  and 
loss  of  sleep,  but  in  difficult  cases  should  have  assist- 
ance. 

Her  duty  to  the  family  demands  that  she  do  every- 
thing in  her  power  to  prevent  other  members  of  the 
family  from  becoming  infected,  and  to  that  end  she 
should  educate  them  in  the  dangers  of  infection  and 
the  precautions  necessary  to  avoid  it. 

Indeed,  one  of  the  greatest  values  of  the  trained  nurse 
lies  in  the  educational  value  of  her  services,  the  example 
of  surgical  cleanliness  which  she  exhibits,  and  the  con- 
ception of  sanitation  and  disease  prevention  which  the 
laity  gain  from  her. 

Her  duty  to  the  public  consists  in  preventing  the 
spread  of  the  infection  by  insisting  upon  the  proper  ob- 
servance of  quarantine,  the  rigid  exclusion  of  flies  and 
domestic  pets,  as  cats  and  dogs,  many  infections  being 
spread  by  these  agencies.  She  should  demand  the  dis- 
infection of  milk  bottles  or  other  utensils  taken  from  the 
place,  and  in  the  absence  of  the  physician  or  other  au- 
thority she  should  oversee  the  process  of  disinfection 
and  fumigation. 

After  leaving  a  case  of  infectious  disease  the  nurse 
should,  if  possible,  determine  if  her  throat  be  free  from 
germs,  that  she  does  not  become  a  healthy  carrier  of 
germs.  She  should  avoid  for  some  time,  if  possible, 


SUSCEPTIBILITY  AND  INFECTION  75 

caring  for  patients  who  would  be  especially  susceptible 
to  the  disease  which  she  has  been  in  contact  with,  such 
as  children  or  confinement  cases  after  scarlet  fever,  and 
surgical  or  obstetric  cases  after  erysipelas  or  septic  in- 
fections. 

SPECIAL  PRECAUTIONS:  DISINFECTION  AND  FUMIGATION 

In  disinfection  in  infectious  disease  the  method  to  be 
followed  depends  upon  the  nature  and  characteristics 
of  the  infecting  agent  and  the  manner  in  which  the  germ 
is  thrown  off.  In  cholera  and  typhoid  fever  the  germ  is 
thrown  off  with  the  urine  and  feces,  while  in  pneumonia, 
diphtheria,  and  tuberculosis  it  is  found  in  the  sputum. 

Typhoid  Fever,  Cholera,  Yellow  Fever. — Exclude 
flies.  The  feces  and  urine  should  be  received  in  a  vessel 
containing  a  5  per  cent,  solution  of  carbolic  acid  or  i :  1000 
solution  of  bichlorid  of  mercury.  They  should  be  al- 
lowed to  stand  an  hour,  being  stirred  several  times  be- 
fore emptying.  The  water-closet,  seat  and  bowl,  and 
the  bed-pan  should  be  washed  daily  with  carbolic  or 
sublimate  solution.  All  bed-linen,  garments,  towels, 
handkerchiefs  worn  or  used  by  the  patient  should  be 
immersed  in  5  per  cent,  carbolic  or  i :  1000  solution  of 
bichlorid  for  an  hour  and  boiled.  Rubber  gloves  should 
be  used  while  bathing  a  patient.  All  vomited  matter 
should  be  disinfected  in  the  same  manner  as  the  stools 
and  urine. 

The  nurse  should,  if  possible,  have  been  vaccinated 


76  BACTERIOLOGY 

against  typhoid.  She  should  disinfect  the  hands  after 
handling  the  patient  with  bichlorid  solution. 

All  dishes,  trays,  glasses,  cups,  and  other  eating 
utensils  should  be  washed  with  bichlorid  and  boiled. 
All  remains  of  liquid  food  should  be  mixed  with  carbolic 
or  sublimate  solution  and  all  solids  burned.  All  toys, 
books,  pencils,  or  writing  material  should  be  disinfected 
before  being  handled  by  others,  or  burned. 

The  patient's  hands  and  parts  of  the  body  that  be- 
come soiled  with  discharges  should  be  washed  with 
i :  1000  bichlorid  solution.  These  precautions  should 
be  followed  until  the  temperature  has  been  normal  at 
least  a  week,  when  the  room  and  furniture  should  be 
disinfected.  All  wood  work,  wooden  furniture,  iron 
beds,  springs,  etc.,  should  be  washed  with  i  :  1000 
bichlorid  solution.  All  rugs,  portieres,  curtains,  and 
draperies  should  have  been  removed  from  the  room. 
If  they  have  not,  those  that  can  be  boiled  should  be,  and 
the  rest  should  be  placed  where  formaldehyd  can  reach 
them  to  the  best  advantage;  the  windows  and  doors 
should  be  sealed  and  formaldehyd  generated  either  with 
a  special  apparatus  or  by  the  permanganate  method,  as 
described  in  an  earlier  chapter. 

Diphtheria,  Scarlet  Fever,  Measles.— Exclude  flies. 
All  precautions  for  typhoid  and  cholera,  except  disin- 
fection of  the  stools  and  urine,  should  be  carried  out  in 
diphtheria,  scarlet  fever,  and  measles,  with  additional 
precautions  to  prevent  the  dissemination  of  the  germs 


SUSCEPTIBILITY  AND  INFECTION  77 

in  the  sputum  and  nasal  secretions;  and  in  scarlet  fever 
and  measles,  in  the  scales.  The  sputum  should  be 
received  in  a  cup  or  receptacle  containing  carbolic  or 
sublimate  solution.  The  patient  should  be  taught  to 
cough  and  blow  the  nose  into  a  rag  or  handkerchief, 
which  should  be  disinfected  or  destroyed. 

In  scarlet  fever  and  measles  the  body  should  be 
anointed  with  camphorated  or  mentholated  oil  to  prevent 
flying  of  the  scales.  A  warm  antiseptic  bath  should  be 
given  daily,  followed  by  the  oil  rub  until  "desquamation 
is  complete.  A  gown  and  overshoes  should  be  kept  out- 
side the  door  for  use  of  doctor  or  others  who  enter  the 
room.  Upon  release  from  quarantine,  the  patient 
should  take  an  antiseptic  bath  and  shampoo,  leave  all 
clothing  in  the  room,  and  dress  in  a  room  which  has  been 
isolated  from  the  sick  room  or  has  already  been  disin- 
fected. The  nurse  should  do  likewise,  all  clothing  being 
left  in  the  room  to  be  fumigated. 

In  diphtheria  it  is  advisable  that  the  nurse  should 
have  an  immunizing  dose  of  antitoxin,  and  wherever 
possible  cultures  should  be  taken  from  her  throat  after 
quarantine  to  see  that  she  does  not  become  a  carrier. 
Should  she  harbor  the  germs  in  her  throat  she  should  not 
go  on  another  case  other  than  diphtheria  until  her  throat 
is  free  from  germs.  After  nursing  scarlet  fever  a  nurse 
should,  wherever  possible,  refuse  to  nurse  a  confinement 
case  or  a  child  with  another  disease  until  some  time  has 
elapsed. 


78  BACTERIOLOGY 

Tuberculosis,  Pneumonia,  and  Influenza. — Exclude 
flies.  In  these  diseases  the  sputum  carries  the  infection; 
the  nasal  secretions  also  in  influenza.  These  secretions, 
therefore,  are  the  ones  that  require  particular  attention. 
They  should  be  carefully  guarded  against  dissemination 
by  the  use  of  sputum  cups  and  gauze  or  handkerchiefs, 
which  may  be  immersed  immediately  in  disinfectant 
solution  or  burned.  Dishes,  eating  utensils,  bed-linen, 
garments,  food,  etc.,  should  receive  the  same  care  as 
in  typhoid  and  other  infectious  diseases.  Rooms  should 
be  disinfected  and  fumigated  as  in  other  infections. 

Small-pox. — Exclude  flies.  In  this  disease  the  scales 
constitute  the  most  important  element  in  the  dissemina- 
tion of  the  infection.  Effort  should,  therefore,  be  di- 
rected toward  eliminating,  as  far  as  possible,  this  source 
of  contagion.  The  contagion  is  very  persistent  and  clings 
to  clothing,  furniture,  the  skin  and  hair  of  attendants, 
and  to  everything  that  may  come  in  contact  with  or  near 
the  patient.  The  room  should  be  as  bare  of  furnishing 
as  possible.  Every  precaution  should  be  exercised  by 
the  physician  and  others  who  must  pass  in  and  out  of  the 
building  where  the  case  is  isolated.  A  complete  outfit 
should  be  at  hand  to  protect  shoes,  clothes,  and  hair  when 
entering  the  room  or  building.  Everyone  in  contact 
with  the  patient  should  have  been  vaccinated.  Anti- 
septic baths  and  shampoos  should  be  given  daily  for 
some  time  before  release.  The  nurse  should  take  simi- 
lar precautions,  though  not  so  extensive.  Fumigation 


SUSCEPTIBILITY  AND  INFECTION  79 

with  formaldehyd  should  be  carried  out  in  the  usual 
manner. 

Cerebrospinal  Meningitis  and  Infantile  Paralysis.— 
Exclude  flies.  While  the  means  of  dissemination  of 
these  diseases  are  not  as  yet  well  understood,  the  fre- 
quent presence  of  the  meningococcus  in  the  secretions  of 
the  nose  and  pharynx,  and  the  fact  that  the  nasal  secre- 
tions in  infantile  paralysis  have  been  shown  to  be  infec- 
tious for  monkeys,  are  sufficient  reasons  for  especial 
attention  to  these  secretions.  The  laws  regarding  quar- 
antine in  these  diseases  are  very  lax  as  yet,  but  strict 
isolation  should  be  insisted  upon  and  every  precaution 
taken  to  prevent  the  spread  of  the  infection,  and  until 
more  complete  knowledge  is  available  regarding  these 
diseases,  fumigation  of  the  rooms  occupied  by  the  pa- 
tient would  be  only  the  part  of  wisdom,  as  would  the 
use  of  Flexner's  antitoxin  on  nurse  and  attendants  in 
meningitis. 

Erysipelas  and  Suppurative  Diseases.— Exclude  flies. 
These,  being  more  especially  surgical  infections,  are  of 
greater  danger  to  persons  having  open  wounds,  to  women 
in  confinement,  etc.  The  precautions  necessary  are 
less  exacting.  Pus,  scales,  crusts,  and  wound  discharges 
should  be  carefully  burned  or  disinfected. 

If  there  be  a  possibility  of  the  room  being  used  for  a 
surgical  confinement  case  at  any  future  time,  it  should 
be  fumigated. 


CHAPTER  XII 

IMMUNITY 

THE  CAUSES  AND  MECHANISM  OF  IMMUNITY 
NATURAL  immunity,  as  we  have  learned,  is  that  re- 
sistance to  certain  diseases  possessed  by  certain  species 
of  animals. 

It  is  dependent  upon  many  different  conditions  and 
circumstances.  Certain  profound  differences  in  the 
life  processes  of  the  different  species  of  animals  are  suffi- 
cient to  account  for  many  instances  of  natural  immu- 
nity. Thus,  the  immunity  of  cold-blooded  animals  to 
most  diseases  of  warm-blooded  species  may  be  ex- 
plained upon  this  ground.  The  tissues  of  the  immune 
individuals  do  not  present  favorable  soil  and  environ- 
ment for  the  growth  and  development  of  the  germs  which 
cause  that  particular  disease.  Just  what  the  condi- 
tions are  which  are  detrimental  to  the  activities  of  the 
germ  we  are  not  able  to  determine  to  any  great  extent. 
True,  we  are  able  in  certain  cold-blooded  animals  to 
convert  this  immunity  into  susceptibility  by  placing  the 
animals  in  a  warm  place.  Doubtless,  by  subjecting  the 
immune  individual  to  the  same  environment,  the  same 
food,  and  the  same  mode  of  living  we  might  be  able  to 

80 


IMMUNITY  81 

influence  the  immunity  to  a  greater  or  less  extent  in 
some  instances.  But  it  is  just  as  probable  that  in  some 
cases  the  immunity  is  dependent  upon  conditions  so 
deep  rooted  and  so  unalterable  as  to  defy  environment, 
food,  or  mode  of  living.  From  which  we  may  gather 
that  in  certain  instances  the  natural  immunity  is  only 
relative,  while  in  others  it  may  be  looked  upon  as  abso- 
lute. Unquestionably,  many  instances  of  natural  im- 
munity are  closely  related  to  acquired  immunity  in 
their  mechanism  and  cause,  and  are  dependent  upon 
the  presence  in  the  tissues  and  body  fluids  of  the  sev- 
eral complex  and  highly  interesting  substances  which 
are  referred  to  collectively  as  antibodies  and  to  the  con- 
ditions which  their  presence  induces.  We  may,  there- 
fore, consider  the  manifestations  of  acquired  immunity 
for  a  better  conception  of  the  natural  form  of  this  con- 
dition. 

ACQUIRED  IMMUNITY 

Acquired  immunity  is  said  to  be  either  active  or  pas- 
sive. Active  immunity  is  that  form  of  immunity  in  the 
production  of  which  the  cells  of  the  individual  take  an 
active  part.  Of  this  character  is  the  immunity  which 
follows  an  attack  of  certain  infectious  diseases,  as  small- 
pox. So  also  is  that  produced  by  inoculation  with  an 
attenuated  form  of  the  disease,  as  in  vaccination  with 
cow-pox,  and  that  produced  by  injections  of  dead  cul- 
tures of  the  causative  germ,  i.  e.,  bacterial  vaccines. 

Passive  immunity  is  defined  as  that  form  of  immun- 

6 


82  BACTERIOLOGY 

ity  in  the  production  of  which  the  cells  of  the  organism 
take  no  part.  It  is  probably  always  artificial,  and  is  ex- 
emplified in  the  use  of  an  immunizing  dose  of  diphtheria 
antitoxin  or  of  tetanus  antitoxin.  The  antitoxin  is  in- 
troduced ready  prepared  into  the  blood  of  the  organism, 
whose  cells  are,  therefore,  under  no  necessity  of  pro- 
ducing further  antitoxin,  and  so  take  no  active 
part  in  the  process.  Such  immunity  is  less  lasting  than 
the  active  form  because  the  antitoxin  is  soon  eliminated, 
while  in  the  active  form  of  immunity  the  cells  go  on 
elaborating  antitoxin  and  other  antibodies  for  a  consid- 
erable tune  after  the  recovery  from  the  disease  or  in- 
oculation whereby  the  immunizing  process  was  brought 
into  action. 

In  the  study  of  active  immunity  numerous  factors 
must  be  taken  into  consideration,  all  of  which  have  a 
part  in  this  complex  phenomenon.  Of  these  factors, 
first  place  is  probably  occupied  by  the  phagocytes,  as 
they  are  doubtless  concerned  in  the  resistance  of  all 
forms  of  infection.  Then  there  are  the  opsonins,  with- 
out which  the  phagocytes  are  helpless.  The  antibodies, 
consisting  of  antitoxins,  bactericides  (alexins,  etc.),  and 
bacteriolysins,  and  lastly,  the  agglutinins,  of  whose 
part  in  the  process  we  are  yet  more  or  less  in  the  dark. 

Of  these  various  substances  and  processes  doubtless 
in  certain  infections  one  plays  a  leading  r61e,  the  others 
being  content  with  minor  parts,  while  in  other  diseases 
their  relative  importance  may  be  reversed,  depending 


IMMUNITY  83 

upon  the  nature  of  the  infection.  In  diphtheria, 
which  is  an  example  of  a  toxemia,  antitoxin  plays  the 
leading  part,  while  the  phagocytes  perform  a  subordinate 
function  in  destroying  the  germs  which  are  producing  the 
toxin.  In  suppurations,  as  in  gonococcus  or  staphylo- 
coccus  infections,  in  which  the  toxins  are  of  secondary 
importance  in  the  production  of  the  diseased  processes, 
phagocytes  and  bacteriolysins  bear  the  burden  of  the 
fight.  Rabbits  and  dogs  are  both  relatively  immune  to 
pneumonia,  but  the  germs  develop  more  readily  in  the 
rabbit  than  in  the  dog.  The  rabbit,  however,  is  less 
susceptible  to  the  poison  than  the  dog,  which  would 
indicate  that  in  the  rabbit  the  antitoxin  was  the  basis 
of  immunity,  while  in  dogs  who  are  susceptible  to  the 
toxins,  but  on  whom  the  germs  do  not  thrive,  the  im- 
munity is  more  than  likely  due  to  the  phagocytosis  or 
the  bactericidal  bodies. 

Briefly  summarized,  the  part  performed  by  the  va- 
rious factors  in  immunity  are  as  follows :  The  phagocytes 
or  white  blood-corpuscles  leave  the  blood-vessels  and 
flock  to  the  site  of  infection  or  the  local  lesion,  there  to 
devour  and  destroy  the  invading  germs. 

The  antitoxins  neutralize  the  toxins  produced  by  the 
germs.  If  the  toxins  are  excreted  by  the  germs  and  taken 
up  by  the  blood,  as  in  diphtheria,  it  does  this  unaided. 
If,  however,  as  in  cholera,  the  germs  themselves  enter 
the  blood  and  carry  their  poisons  within  their  bodies, 
the  bacteriolysins  must,  by  dissolving  the  germs,  set 


84  BACTERIOLOGY 

the  toxin  free  before  it  can  be  neutralized  by  the  anti- 
toxin, but  before  the  bacteriolysins  can  dissolve  the 
germs  it  is  necessary  for  the  bactericides  or  alexins  to 
destroy  them. 

If  these  substances  for  a  certain  germ  (for  it  should 
be  understood  that  they  differ  for  different  germs) 
exist  in  sufficient  quantities  and  the  processes  described 
are  sufficiently  active,  immunity  to  that  germ  must 
exist.  If  these  immunizing  substances  be  not  present, 
the  introduction  of  the  germ  into  the  body  stimulates 
their  formation,  and  if  recovery  occurs,  they  remain  in 
the  body  in  sufficient  quantities  to  prevent  any  such 
germ  from  obtaining  a  foothold  in  that  territory  for  a 
varying  length  of  time. 

Whether  natural  immunity  to  toxin  is  due  to  the  pres- 
ence in  the  blood  of  antitoxin  or  to  a  lack  of  affinity 
between  the  toxin  and  the  body  cells,  or  to  both,  we  are 
unable  to  say.  It  is  a  fact  that  in  some  instances  anti- 
toxin is  found  in  the  blood  of  healthy  animals  which 
are  immune  to  a  certain  toxin.  In  others  no  such  anti- 
toxin is  present,  and  yet  immunity  exists,  due  perhaps 
to  a  lack  of  affinity  between  the  toxin  and  the  cells  of  the 
organism.  The  tortoise  is  unaffected  by  injections  of 
tetanus  toxin,  but  if  the  blood  of  a  tortoise  which  has 
been  injected  with  tetanus  toxin  be  injected  into  a  sus- 
ceptible animal,  death  results,  showing  that  the  toxin 
is  not  neutralized  by  the  antitoxin  or  otherwise  de- 
stroyed. 


IMMUNITY  85 

INHERITED  IMMUNITY 

Natural  immunity  is,  of  course,  transmitted  from 
parent  to  offspring,  but  acquired  immunity  is  transmitted 
but  slightly,  if  at  all.  A  certain  degree  of  immunity  is 
transmitted  by  the  female  immunized  animal  to  her  off- 
spring in  certain  instances,  as  in  the  case  of  sheep  im- 
munized to  anthrax,  but  this  does  not  obtain  in  case  of 
the  male  parent. 

A  certain  degree  of  passive  immunity  occurs  in  the 
newborn  whose  mother  has  had  recent  injections  of 
antitoxin.  Antitoxin  may  also  be  transmitted  from 
mother  to  offspring  through  the  milk.  The  immunity 
thus  conferred  is  not  sufficient  to  be  depended  upon,  and 
further  immunizing  procedures  should  always  be  insti- 
tuted. Agglutinins  are  occasionally  transmitted  to  the 
offspring.  Opsonins  are  not  transmitted  to  the  offspring 
in  the  uterus,  but  are  present  in  the  milk  of  nursing 
animals,  and  they  are  probably  absorbed  by  the  nurs- 
ling via  the  digestive  tract. 

METHODS  OF  PRODUCING  ACTIVE  ACQUIRED  IMMUNITY 
Inoculation  with  Living  Virulent  Bacteria. — This  form 
of  inducing  immunity  is  impractical  and  little  used. 
It  has  been  resorted  to  experimentally  with  more  or 
less  success  in  animals  of  diminished  susceptibility. 
Small  non-fatal  doses  are  administered  and  gradually 
increased.  The  only  instance  of  the  use  of  this  method 
in  man  is  in  Ferran's  inoculation  against  cholera. 


86  BACTERIOLOGY 

Advantage  is  taken  in  this  method  of  the  relative 
immunity  to  infection  by  other  than  the  usual  route  of 
infection.  The  avenue  of  infection  in  this  disease  is 
the  intestinal  tract.  By  subcutaneous  injection  of 
virulent  cholera  germs  a  local  reaction  is  produced  with 
slight  constitutional  disturbances,  which,  however,  is 
sufficient  to  produce  immunity  to  the  disease. 

Inoculation  with  Living  Bacteria  of  Attenuated  Viru- 
lence.— In  this  method  of  securing  immunity  the  viru- 
lence of  the  causative  germ  is  diminished  by  various 
procedures,  as  by  cultivating  them  in  the  presence  of 
antiseptics,  as  in  anthrax;  by  cultivating  in  high  tem- 
perature, also  used  for  anthrax  vaccines;  by  drying,  as 
in  vaccination  for  hydrophobia;  by  passing  through  an 
unfavorable  host,  as  in  small-pox  vaccination.  Im- 
munization for  anthrax  in  animals  and  for  small-pox  in 
man  are  examples  of  this  form  of  active  immunization. 

Inoculation  with  Dead  Bacteria  (Bacterial  Vaccines). 
— This  method  of  securing  immunity  is  the  most  prac- 
tical and  of  the  widest  application  of  perhaps  all  the 
methods  of  securing  active  immunization.  In  connec- 
tion with  the  use  of  the  opsonic  index  it  is  becoming  of 
increasing  importance  in  the  prevention  of  bacterial 
disease.  The  most  important  example  of  this  form  of 
immunization  in  man  is  in  the  vaccination  against  ty- 
phoid fever.  It  is  also  used  in  vaccination  against  chol- 
era and  plague. 

Inoculation  with  Bacterial  Toxin.— This  method  of 


IMMUNITY  87 

producing  immunity  is  little  used  in  man.  The  most 
important  example  of  its  use  is  in  the  immunization  of 
the  horse  against  diphtheria  for  the  production  of  anti- 
toxin, also  in  the  production  of  tetanus  antitoxin. 
While  the  results  of  this  method  are  usually  attributed  to 
the  toxin,  it  is  probable  that  other  products  of  bacterial 
activity  play  a  part,  as  the  broth  upon  which  the  bac- 
teria have  been  cultivated  is  separated  from  the  germs 
by  nitration  and  injected,  and  in  all  likelihood  contains 
other  substances  besides  toxin.  The  employment  of 
tuberculin  for  the  production  of  immunity  is  a  combi- 
nation of  this  method  with  the  use  of  the  dead  germs. 


CHAPTER  XIII 

SERUM   THERAPY    AND   VACCINE    THERAPY,   ANTI- 
TOXINS, SERUMS,  AND    VACCINES 

SERUM  THERAPY 

Definition. — The  treatment  of  disease  by  the  use  of 
the  serum  of  immunized  animals. 

Serum  therapy  may  be  said  to  have  originated  with 
the  discovery  of  diphtheria  and  tetanus  antitoxin  by 
Behring  and  Kitasato  in  1890,  and  vaccine  therapy  by 
the  discovery  by  Koch,  in  the  same  year,  of  tuberculin. 
Disastrous  results  following  the  use  of  tuberculin  in 
unselected  cases  and  improper  doses  led  to  its  abandon- 
ment for  a  time,  but  antitoxin,  being  more  universally 
applicable,  more  specific  in  its  action,  and  less  potent  of 
harm,  sprang  into  immediate  and  continued  use.  More 
careful  and  painstaking  employment  of  tuberculin  with 
greater  knowledge  of  its  action  has  served  to  prove  its 
usefulness  not  alone  as  a  diagnostic  measure,  but  also  as 
a  therapeutic  agent  in  the  treatment  of  tuberculosis. 

These  discoveries,  together  with  the  development  of 
vaccine  therapy  and  the  opsonic  index  by  Wright,  of 
England,  have  done  more  to  make  medicine  an  exact 
science  than  any  other  discoveries  occurring  in  a  century 


SERUM  THERAPY  89 

past.  With  the  single  exception  of  Ehrlich's  "606"  in 
the  treatment  of  syphilis,  it  may  be  said  that  every  ad- 
vance that  has  been  made  in  the  conquest  of  disease 
has  been  along  the  line  of  serum  therapy,  and  the  hope 
of  the  future  certainly  seems  to  lie  within  its  magic 
realm.  And  who  that  has  watched  the  dark  and  grue- 
some membrane  spreading  like  a  pall  across  the  throat 
of  an  innocent  child,  shrivel,  and  shrink  and  loose  its 
tenacious  hold,  that  has  felt  the  harried  pulse  drop  into 
peaceful  rhythm,  and  seen  the  haunted  look  leave  the 
eyes  of  one  of  these  little  sufferers,  but  has  felt  the  magic 
of  its  power,  has  felt  that  here,  among  all  its  vast  uncer- 
tainties, medicine  reigned  secure. 

ANTITOXIN 

The  principle  upon  which  the  antitoxin  treatment  of 
disease  depends  is  the  production  within  the  body  of 
an  animal  affected  with  disease  of  certain  antibodies 
which  combine  chemically  with  the  toxins  of  the  dis- 
ease, rendering  them  inert  and  harmless,  hence  the  term 
antitoxin.  Upon  the  number  and  activity  of  the  anti- 
bodies present  in  any  particular  case  depends  the  out- 
come of  the  disease,  whether  recovery  or  death,  and  it  is 
the  province  of  this  particular  form  of  serum  therapy 
to  assist  nature  and  increase  the  antibodies  by  supplying 
them  from  an  outside  source,  such  outside  source  being 
usually  the  horse,  in  which  they  have  been  cultivated 
by  the  systematic  injection  of  increasing  doses  of  the 


go  BACTERIOLOGY 

toxin  of  the  disease,  the  introduction  of  the  toxins  of  a 
disease  into  a  susceptible  animal  having  been  found  to 
give  rise  to  an  elaboration  of  antitoxin  just  as  does  an 
attack  of  the  disease. 

The  therapeutic  action  of  antitoxin  is  essentially  a 
chemical  one,  depending  upon  the  affinity  between  the 
antibodies  produced  by  the  cells  of  the  organism  and  the 
toxin  produced  by  the  germs.  The  product  of  such 
chemical  union  of  toxin  and  antitoxin  is  a  harmless 
substance,  just  as  is  the  product  of  the  chemical  action 
which  takes  place  between  the  ordinary  inorganic  poi- 
sons and  their  antidotes,  of  which  we  study  in  toxi- 
cology. 

It  is  probable  that  the  toxin  also  has  an  affinity  for 
the  tissue  cells  of  the  body,  and  combines  with  them 
somewhat  less  readily  than  with  antitoxin.  When  such 
union  takes  place,  it  becomes  necessary  for  larger  quan- 
tities of  antitoxin  to  be  produced  or  introduced  from 
without  in  order  to  cause  the  toxin  to  leave  the  tissue 
cells  which  they  tend  to  destroy,  and  unite  with  the 
antitoxin  which  renders  them  inert.  We  can,  there- 
fore, readily  understand  the  necessity  for  the  early  ad- 
ministration of  antitoxin,  and  also  of  the  administra- 
tion of  larger  doses  when  not  given  early. 

It  is  probable  that  the  affinity  of  toxin  for  tissue  cells 
is  greater  hi  some  cases  than  in  others.  This  is,  doubt- 
less, especially  true  of  the  toxin  of  the  tetanus  germ, 
for  the  cells  of  the  central  nervous  system,  and  accounts 


SERUM  THERAPY  91 

for  the  well-established  fact  that  to  be  of  much  value 
tetanus  antitoxin  must  be  administered  before  the  ad- 
vent of  convulsions  which  mark  the  attack  of  the  poison 
upon  the  nervous  tissue. 

Diphtheria  Antitoxin. — Preparation. — The  method  of 
preparing  antitoxin  followed  by  the  firm  of  H.  K.  Mul- 
ford  Company  may  be  taken  as  fairly  representative  of 
the  process  followed  by  all  manufacturers  of  antitoxin, 
and  is,  therefore,  described  herewith. 

Preparation  of  the  Toxin. — A  virulent  culture  of  diph- 
theria germs  is  grown  in  pure  culture  on  specially  pre- 
pared media  in  incubators  and  under  the  most  favorable 
conditions  for  the  production  of  toxin.  After  five  to 
seven  days'  growth  trikresol  is  added  to  kill  the  germs, 
which  are  then  removed  by  filtration  through  a  Berke- 
feld  filter.  The  toxin  is  then  tested  for  strength  by 
determining  the  minimum  fatal  dose  for  a  guinea-pig 
of  certain  weight  in  a  definite  length  of  time. 

Injecting  the  Horse. — The  toxin  having  been  obtained, 
a  small  amount  is  injected  into  a  horse,  and  the  sub- 
sequent reaction,  temperature,  and  pulse  carefully 
noted.  With  the  subsidence  of  the  reaction,  another 
and  larger  dose  of  the  toxin  is  administered,  and  this  is 
repeated,  gradually  increasing  the  dosage  until  the 
horse  ceases  to  react  to  large  doses  of  toxin  or  until,  in 
other  words,  he  is  immune  to  the  toxin,  when  his  blood 
will  be  found  to  be  charged  with  antitoxin. 

It  will  be  noted  that  the  horse  is  not  infected  with 


92  BACTERIOLOGY 

diphtheria,  the  germ  having  been  carefully  killed  and 
removed  from  the  toxin  before  its  use.  The  effect  of 
the  injection  of  the  toxin  bears  out  the  statement  made 
earlier  in  this  work  that  the  symptoms  arising  from  in- 
fection with  the  various  disease  germs  were  due  to  the 
toxins  produced  by  the  germ,  rather  than  to  the  presence 
of  the  germs  themselves  in  the  tissues  of  the  infected 
animal. 

Selection  and  Care  of  Horse. — The  horse  is  selected  for 
the  production  of  an  antitoxin  because  he  is  naturally 
relatively  immune  to  diphtheria,  as  well  as  tuberculosis 
and  other  diseases,  and  furnishes  a  large  quantity  of 
serum.  Only  healthy  animals  are  selected.  They  are 
tested  for  glanders  with  mallein,  and  kept  constantly 
immunized  to  tetanus  by  injections  of  tetanus  antitoxin. 
They  are  carefully  cared  for  and  every  precaution  exer- 
cised to  keep  them  in  perfect  health. 

After  the  horse  has  ceased  to  react  to  further  injec- 
tions of  toxin,  he  is  bled.  He  is  prepared  as  for  a  sur- 
gical operation.  Covered  with  a  sterile  sheet,  taken  into 
a  specially  prepared  operating-room,  where,  under  the 
strictest  aseptic  precautions,  the  jugular  vein  is  opened 
and  from  3  to  5  quarts  of  blood  removed  and  received  in 
a  covered  sterile  jar,  which  is  placed  in  a  special  room  and 
allowed  to  clot,  when  the  serum  which  contains  the  anti- 
bodies can  be  separated  from  the  clot  or  fibrin  and  red 
corpuscles.  After  a  few  days'  rest  the  horse  is  ready  for 
further  toxin  administration. 


SERUM  THERAPY  93 

Testing  the  Serum  for  Strength. — A  standard  of  strength 
for  antitoxin  is  established  by  the  government,  which 
provides  the  manufacturing  laboratories  with  small 
quantities  of  test  antitoxin  for  determining  the  test  dose 
of  toxin  with  which  to  test  the  antitoxin  manufactured. 
The  amount  of  test  toxin  which  when  mixed  with  one 
unit  of  the  test  antitoxin  furnished  by  the  government 
will  kill  a  guinea-pig  weighing  250  grams  in  just  four  days 
is  termed  the  test  dose  of  toxin.  The  smallest  amount 
of  serum  which  will  save  or  prolong  a  25o-gram  pig's  life 
just  four  days  when  injected  with  the  test  dose  of  toxin 
will,  therefore,  be  said  to  contain  a  unit  of  antitoxin. 
If,  therefore,  it  requires  ^75-  c.c.  of  serum  to  save  the 
pig's  life  for  four  days,  the  serum  will  contain  400  units 
of  antitoxin  per  cubic  centimeter.  After  the  strength 
of  the  serum  has  been  determined,  a  small  amount  of 
trikresol,  a  harmless  antiseptic,  is  added  to  prevent 
contamination  in  handling  the  serum  after  it  leaves  the 
laboratory,  and  the  serum  is  tested  for  sterility. 

Testing  for  Bacteria. — A  small  quantity  of  the  serum 
is  mixed  with  an  equal  quantity  of  sterile  bouillon  and 
placed  in  an  incubator,  where  it  is  kept  for  five  days, 
when  it  is  examined  microscopically  and  a  portion  in- 
jected into  a  guinea-pig,  which  is  watched  for  several 
days  for  symptoms  of  infection  of  any  kind.  Should 
it  not  be  found  sterile,  the  entire  lot  is  rejected. 

Antidiphtheric  Globulins  or  Concentrated  Antitoxins. 
— It  has  been  determined  that  the  real  antibodies  of  the 


94  BACTERIOLOGY 

serum  were  certain  protein-like  bodies  called  globulins, 
and  that  by  a  process  of  precipitation  and  nitration 
these  could  be  separated  from  the  inert  elements  of  the 
serum,  thus  reducing  the  bulk  of  the  dose  to  be  injected 
and  removing  some  of  the  objectionable  effects  which 
sometimes  followed  the  injection  of  large  doses  of  the 
non-concentrated  antitoxin,  such  as  urticaria,  rashes, 
etc. 

Marketing  Antitoxin. — The  antitoxin  is  finally  placed 
in  specially  devised  containers,  which  are  made  in  the 
form  of  a  syringe  with  needle  attached,  each  container 
holding  from  500  to  5000  units  of  antitoxin.  The  con- 
tainer is  sterilized  and  packed  in  an  aseptic  package 
which  may  be  opened  at  the  bedside  and  found  ready 
for  instant  use. 

Dosage  and  Administration. — As  an  immunizing  dose, 
that  is,  such  as  will  prevent  one  who  has  been  exposed 
to  the  disease  from  becoming  infected,  500  to  1000  units 
may  be  given,  depending  upon  the  age  or  size  of  the 
individual. 

A  curative  dose  should  never  be  less  than  3000  units, 
and  5000  had  better  be  given  at  the  beginning  of  any 
case  if  seen  early.  If  the  case  be  not  seen  until  it  is 
well  advanced,  one  should  not  temporize,  but  should 
give  10,000  units  at  once,  and  repeat  the  dose  in  four  to 
five  hours  if  decided  improvement  has  not  occurred. 

Large  doses  can  do  no  harm,  and  it  must  be  remem- 
bered that  the  longer  the  disease  has  been  in  progress  the 


SERUM  THERAPY  95 

more  toxin  there  is  in  the  body  that  must  be  neutralized 
before  recovery  can  occur. 

Administration. — The  loose  skin  of  the  buttocks, 
between  the  shoulders,  or  of  the  anterior  abdominal 
wall  is  usually  selected  as  the  site  of  injection.  The 
skin  should  be  thoroughly  scrubbed  with  soap  and  water, 
followed  by  alcohol  or,  what  is  more  efficient,  simply 
painted  at  the  point  of  injection  with  tincture  of  iodin. 
The  syringe  container  is  removed  from  its  package 
with  sterile  hands  and  its  contents  injected  into  the  sub- 
cutaneous cellular  tissue.  A  drop  of  collodion  may  be 
applied  to  the  needle  wound. 

Effects. — If  the  dose  has  been  sufficient  within  a 
short  time,  varying  with  the  severity  of  the  disease  and 
the  period  of  administration,  improvement  in  all  the 
symptoms  will  be  manifest.  The  temperature  will  fall, 
the  pulse  improve,  the  membrane  cease  to  advance 
and  begin  to  loosen  up  at  the  borders,  being  finally 
coughed  up  piecemeal  or  en  masse.  Should  such  im- 
provement not  occur  within  five  or  six  hours,  it  is 
evidence  sufficient  that  the  dose  has  not  been  large 
enough,  and  that  another  and  larger  dose  should  be 
injected. 

Tetanus  antitoxin  is  prepared  from  the  horse  in  prac- 
tically the  same  manner  as  the  diphtheria  antitoxin. 
Tetanus  toxin  is  injected  in  increasing  doses  until  the 
horse  ceases  to  react,  when  he  is  bled  and  the  serum 
separated,  as  in  the  manufacture  of  the  diphtheria  serum. 


96  BACTERIOLOGY 

It  is  marketed  in  the  syringe  containers  and  also  in 
powder  form  for  use  in  the  treatment  of  suspected 
wounds. 

Use,  Administration,  and  Dosage. — Wassermann  and 
Takaki  found  that  after  mixing  tetanus  toxin  with  brain 
,substance  it  could  be  injected  into  animals  with  im- 
punity. So  firmly  is  the  toxin  united  to  the  brain  cells 
that  it  fails  to  affect  the  tissues  of  the  animal  into  which 
it  is  injected. 

Owing  to  the  peculiar  affinity  of  the  tetanus  toxin  for 
the  cells  of  the  central  nervous  system,  as  shown  by 
the  above  experiment  and  as  borne  out  by  the  charac- 
teristic symptoms  of  the  disease,  the  greatest  value  of  the 
antitoxin  lies  in  its  use  as  a  preventive  rather  than  as 
a  curative  measure.  Therefore,  all  punctured  wounds 
of  a  suspicious  character,  as  nail  wounds,  blank-cartridge 
wounds,  and  wounds  likely  to  be  contaminated  with 
garden  earth  or  stable  manure,  should  be  thoroughly 
opened  to  the  air,  dusted  with  antitetanic  dusting- 
powder,  and  a  full  dose  (15,000  units)  of  the  serum  in- 
jected at  the  earliest  possible  moment.  This  should  be 
repeated  in  eight  or  ten  days.  When  the  disease  is 
already  established,  in  addition  to  large  and  repeated 
doses  subcutaneously,  the  antitoxin  may  be  introduced 
into  the  spinal  canal  by  lumbar  puncture,  that  it  may  be 
brought  into  immediate  contact  with  the  toxin  in  the 
central  nervous  system.  The  wound  should  be  laid 
open  by  free  incision,  and  the  antitoxin  used  in  and  about 


SERUM  THERAPY  97 

the  wound  in  hopes  of  rendering  inert  any  toxin  which 
has  not  yet  entered  the  circulatory  system. 

Antimeningitis  Serum. — This  serum,  like  others,  is 
prepared  from  the  horse.  In  the  beginning,  alternate 
injections  of  dead  cultures  of  diplococcus  meningitidis 
and  cultures  which  have  undergone  autolysis  are  injected. 
Autolysis  is  a  process  of  self-destruction  of  the  germs 
which  takes  place  as  follows:  10  to  20  c.c.  of  normal 
salt  solution  is  poured  over  a  twenty-four-hour  culture 
of  the  germ.  The  cultures  are  separated  from  the 
medium  by  agitation  and  the  flask  placed  in  an  incubator 
for  twenty-four  hours,  when  the  fluid  resulting  will  be 
found  free  from  diplococci  and  to  contain  only  granular 
debris  and  solution  of  diplococci.  After  several  weeks 
the  dead  culture,  which  is  alternated  with  the  autolysate, 
is  replaced  by  living  cultures.  The  injections  are  con- 
tinued in  increasing  doses  over  a  period  of  four  to  six 
months,  when  the  serum  of  the  animal  is  tested.  When 
it  is  found  active  in  a  dilution  of  i :  5000  it  is  considered 
fit  for  use,  and  the  horse  is  bled  and  the  serum  preserved 
as  are  other  serums. 

Action  of  the  Serum. — The  mode  of  action  of  antimen- 
ingitis  serum  is  probably  more  complicated  than  that 
of  antidiphtheric  serum.  It  seems  to  combine  the 
action  of  a  bacterial  vaccine  with  that  of  an  antitoxin. 
By  its  opsonic  action  it  increases  phagocytosis.  The 
phagocytic  destruction  of  the  diplococci  sets  free  their 
toxin,  which  the  antibodies  of  the  serum  are  then  able 
7 


gS  BACTERIOLOGY 

to  combine  with  and  render  inert.  Until  the  toxins 
are  set  free  from  the  germ  the  antibodies  are  unable  to 
combine  with  them,  hence  the  phagocytic  destruction 
of  the  germs  is  necessary  to  the  success  of  the  treatment. 

Method  of  Administration,  Dosage,  etc. — Because  the 
phagocytic  action  of  the  serum  occurs  only  in  concen- 
trated solutions  and  because  this  must  precede  its  an- 
titoxic action,  the  serum  is  injected  directly  into  the 
spinal  canal  where  it  can  come  into  direct  contact  with 
the  germs  with  a  minimum  of  dilution. 

The  dose  is  from  20  to  45  c.c.  in  adults  and  10  to  30 
c.c.  in  children.  A  similar  amount  of  cerebrospinal 
fluid  is  withdrawn  by  lumbar  puncture  and  the  serum 
introduced  in  its  stead. 

The  dose  should  be  repeated  for  three  or  four  consec- 
utive days  unless  the  improvement  is  so  great  as  to 
warrant  the  discontinuance  of  the  treatment.  The  best 
guide  is  the  condition  of  the  spinal  fluid,  which  should 
be  examined  at  frequent  intervals.  As  long  as  it  shows 
the  presence  of  meningococci  the  injections  should  be 
continued. 

Results  of  Treatment. — When  the  serum  is  used 
early  and  in  sufficient  doses  the  results  are  extremely 
gratifying.  Coma,  headache,  delirium,  and  insomnia 
disappear  at  once.  The  temperature  falls  perhaps  to 
normal.  The  paralysis  improves  or  entirely  disappears. 
In  fact,  the  cases  which  recover  are  entirely  free  from 
the  hideous  deformities  and  defects,  such  as  deafness, 


SERUM  THERAPY  99 

blindness,  and  various  paralyses,  which  attend  the 
cases  that  recover  without  the  serum.  The  mortality 
has  been  reduced  from  65  to  80  per  cent,  without  the 
use  of  the  serum  to  18  to  25  per  cent,  when  the  serum 
has  been  administered. 

Infantile  Paralysis. — While  the  germ  of  this  disease 
remains  unidentified,  Flexner  has  been  able  to  transmit 
the  infection  from  one  monkey  to  another;  has  demon- 
strated that  flies  may  carry  the  virus  from  one  monkey 
to  another;  and,  lastly,  has  perfected  a  serum  with 
which  he  is  able  to  render  monkeys  immune  to  the 
virus  of  the  disease  which  is  found  to  exist  in  the  spinal 
cord,  the  nasal  secretions,  etc.,  of  the  animals.  This 
serum  is  not  at  this  writing  perfected  for  use  in  the  hu- 
man being,  but  there  seems  every  reason  to  believe 
that  it  soon  will  be. 

Typhoid  Antitoxin. — Chantemesse,  of  Paris,  has  suc- 
ceeded in  isolating  a  typhoid  toxin  and  rendering  horses 
immune  by  injections  of  increasing  doses  of  the  toxin. 
He  has  thus  been  able  to  produce  an  antitoxin  with 
which  he  claims  to  have  reduced  the  hospital  mortality 
of  typhoid  from  18  to  4  per  cent. 

Owing  to  the  difficulty  encountered  in  the  manufac- 
ture of  this  serum  and  its  expense,  it  is  not  much  used 
as  yet,  but  there  seems  no  doubt  that  its  use  is  of  con- 
siderable value  in  the  treatment  of  this  disease. 

Bubonic  Plague  Antitoxin  (Yersin's  Serum). — The 
method  of  preparation  of  this  serum  is  very  similar  to 


ioo  BACTERIOLOGY 

that  used  in  the  manufacture  of  diphtheria  antitoxin. 
Fresh  agar  cultures  of  the  Bacillus  pestis  are  sterilized 
by  heat  and  injected  into  horses  in  increasing  doses. 
From  six  months  to  a  year  is  required  for  the  produc- 
tion of  an  active  serum.  It  has  been  found  difficult  to 
standardize,  but  the  endeavor  is  to  produce  a  serum 
TV  c.c.  of  which  will  protect  a  mouse  from  a  dose  of  the 
germs  which  kills  a  control-mouse  in  three  days.  The 
serum  is  used  by  injection,  the  dose  being  60  to  150  c.c. 
Like  other  antitoxins,  it  is  most  efficacious  when  ad- 
ministered early. 

Its  use  as  a  prophylactic  is  attended  with  most  excel- 
lent results,  but  the  protection  afforded  only  lasts  for 
fifteen  days,  so  that  to  be  effective  over  a  longer  period 
of  time  it  must  be  administered  at  intervals  of  ten 
days  to  two  weeks.  It  has  been  recommended  that  it 
be  used  in  connection  with  Haffkine's  vaccine  as  a 
prophylactic  measure,  a  more  lasting  immunity  being 
thus  established. 

VACCINE  OR  OPSONIC  THERAPY 

Vaccine  therapy  is  based  upon  the  principle  of  phago- 
cytosis and  the  opsonic  theory  of  that  process.  As 
has  been  shown  in  the  discussion  of  immunity,  the  leu- 
kocytes play  an  important  r61e  in  the  protection  of  the 
individual  against  certain  diseases.  We  have  also 
noted  that  their  activity  and  ability  to  attack  disease 
germs  depends  upon  the  presence  in  the  blood  of  cer- 


VACCINE  OR  OPSOlftC  THERAPY  101 

tain  substances  termed  opsonins,  which  prepare  the 
bacteria  for  destruction  by  the  phagocytes,  that  is,  so 
act  upon  the  bacteria  as  to  render  them  susceptible 
to  the  action  of  the  phagocytes.  Wright  discovered  that 
the  amount  of  these  opsonins  in  the  blood  which,  by 
the  way,  differ  for  different  bacteria,  could  be  increased 
for  any  particular  germ  by  injection  into  the  body  of 
dead  cultures  of  that  germ.  These  dead  cultures  are 
called  bacterial  vaccines.  They  should  not  be  confused 
with  the  vaccines  for  small-pox  and  anthrax,  which 
depend  upon  a  different  principle,  which  will  be  consid- 
ered later. 

The  Opsonic  Index. — The  amount  of  opsonins  for 
a  certain  germ  present  in  the  blood  of  an  individual  may 
be  determined  in  the  following  manner: 

Equal  volumes  of  blood-serum  and  of  leukocytes  from 
the  blood  of  the  individual,  which  have  been  Washed  with 
normal  salt  solution,  and  of  emulsion  of  a  culture  of 
the  germ  in  question,  are  mixed  and  placed  in  an  incu- 
bator for  fifteen  minutes.  We  have  then  phagocytes, 
germs,  and  blood-serum  containing  the  opsonins,  more 
or  less  of  which  the  individual  may  be  possessed.  Cover- 
slips  of  the  mixture  are  then  made,  stained,  and  examined 
under  the  microscope,  when  the  number  of  bacteria 
contained  in  each  leukocyte  may  be  seen  and  counted. 
The  number  of  bacteria  in  50  or  more  leukocytes  are 
counted  and  averaged. 

The  opsonic  index  is  simply  a  method  of  expressing 


102  BACTERIOLOGY 

the  relative  amount  of  opsonins  in  an  individual's  blood 
when  compared  with  a  normal  standard.  If  the  average 
number  of  germs  contained  in  a  leukocyte  in  a  normal 
serum  were  5,  and  the  average  of  the  individual's  blood 
Under  examination  but  3,  his  opsonic  index  would  be 
said  to  be  3  divided  by  5,  or  f,  or  .60. 

If  under  these  circumstances  a  certain  number  of  dead 
germs  be  injected  into  this  individual  after  a  certain 
length  of  time,  an  examination  of  the  blood  will  show  an 
increased  number  of  bacteria  hi  each  leukocyte.  The 
opsonic  index  is  said  to  have  been  raised. 

Like  antitoxins,  bacterial  vaccines  are  not  only  of 
value  in  the  treatment  of  infections,  but  they  may  also 
be  used  in  the  prevention  of  infection.  This  is  particu- 
larly true  of  typhoid  vaccine,  which  confers  a  marked 
degree  of  immunity  to  typhoid  fever. 

Immediately  following  the  administration  of  a  bacteria 
vaccine  there  occurs  a  diminution  of  the  opsonins,  which 
lasts  for  a  variable  length  of  time.  This  is  termed  the 
negative  phase.  This  is  followed  shortly  by  the  increase 
of  opsonins,  or  the  positive  phase. 

It  has  been  contended  by  some  that  hi  protective 
vaccination  this  so-called  negative  phase  lays  the  sub- 
ject more  liable  to  infection  during  this  time.  Experi- 
ments, however,  have  shown  that  this  phase  may  be 
practically  abolished  by  using  very  small  initial  doses  of 
the  vaccine,  repeating  the  vaccinations  with  larger  doses 
later,  that  is,  in  eight  to  ten  days. 


VACCINE  OR  OPSONIC  THERAPY  103 

BACTERIAL  VACCINES 

Autogenous  Vaccines. — It  has  been  held  by  some  that 
there  are  different  strains  or  varieties  of  the  same  germ, 
and  that  to  be  of  value  the  vaccine  must  be  made  from 
the  identical  strain  with  which  the  individual  is  infected 
by  making  cultures  from  the  site  of  infection.  Such 
vaccines  are  called  autogenous  vaccines,  in  contradis- 
tinction to  stock  vaccines  which  are  prepared  from  other 
sources. 

Stock  Vaccines. — These  are  made  from  cultures  of  the 
germ  of  other  origin  than  the  particular  case  in  which 
they  are  intended  to  be  used.  They  are  prepared  from 
pure  cultures  of  different  germs  of  various  origin,  and 
are  put  up  in  aseptic  containers  and  kept  ready  for  use. 

They  have  the  advantage  of  being  ready  for  immediate 
use,  thus  avoiding  the  loss  of  time  necessary  to  grow  the 
germ  in  pure  culture  from  the  local  infection  in  the 
preparation  of  autogenous  vaccines.  The  question  of 
the  superiority  of  the  autogenous  vaccines  is  still  un- 
settled. In  the  preparation  of  vaccines  the  germs  are 
grown  in  pure  culture  killed  by  heat  and  diluted  with 
normal  salt  solution  until  each  cubic  centimeter  con- 
tains a  definite  number  of  germs  which  differ  for  the 
different  bacteria. 

Staphylococcus  Vaccines. — These  have  been  used  with 
success  in  treatment  of  boils,  carbuncles,  pyorrhea  alve- 
olaris,  sycosis,  etc.  Stock  vaccines  are  prepared  of 
Staphylococcus  aureus.  Staphylococcus  albus,  and 


104  BACTERIOLOGY 

Staphylococcus  citreus,  and  also  of  all  three  combined, 
for  the  treatment  of  infections  where  all  three  exist 
together.  Each  cubic  centimeter  contains  400,000,00x3 
bacteria.  The  dose  should  be  about  100,000,000  to 
begin  with,  and  increased  according  to  the  patient's 
tolerance.  Five  to  eight  days  should  elapse  between 
doses. 

Streptococcus  Vaccine. — This  has  been  used  with 
rather  meager  results.  Some  benefit  is  claimed  for  it 
in  sepsis  and  in  scarlet  fever,  but  the  benefit  derived 
from  its  use  is  less  than  from  most  any  of  the  bacterial 
vaccines.  Doubtless  the  variety  of  strains  of  this  germ 
or  its  varying  behavior  under  differing  conditions  may 
account  for  the  lack  of  success  of  vaccine  therapy  in 
treating  infections  with  it. 

Gonococcus  Vaccine. — This  has  been  used  with  good 
results  in  the  chronic  form  and  in  the  complications  of 
this  disease,  as  in  arthritis,  prostatitis,  endocarditis, 
etc.  Its  value  as  an  immunizing  agent  has,  fortunately, 
not  been  established. 

Bubonic  Plague  Vaccine  (Haffkine's  Prophylactic).— 
This  vaccine  is  produced  by  growing  Bacillus  pestis 
upon  broth.  After  the  growth  has  proceeded  for  a 
month  or  six  weeks,  the  culture  is  sterilized  by  heating 
and  tested  for  sterility  upon  mice,  when  it  is  ready  for 
use. 

Administration  and  Dosage. — The  dose  is  from  i  to 
3  c.c.,  administered  by  injection.  The  administration 


VACCINE  OR  OPSONIC  THERAPY  105 

is  followed  by  general  and  local  disturbances  similar 
to  those  following  typhoid  vaccination.  There  is  some 
redness  and  swelling  at  the  site  of  injection,  fever, 
nausea,  and  general  malaise,  all  of  which  pass  off  in 
from  twenty-four  to  thirty-six  hours. 

Effects. — The  immunity  conferred  is  not  as  great  as  in 
typhoid  and  appears  to  disappear  in  about  six  months. 
The  vaccination  should  be  repeated  in  ten  to  fifteen 
days  to  make  the  protection  more  certain.  It  is  believed 
that  a  greater  protection  is  afforded  by  combining  the 
vaccine  with  the  administration  of  Yersin's  antitoxin. 

Typhoid  Vaccine. — This  is  prepared  by  cultivating  a 
strain  of  typhoid  bacilli  of  diminished  virulence.  The 
culture  is  killed  by  heat,  a  small  amount  of  antiseptic 
added  to  prevent  contamination  in  handling,  and  the 
culture  diluted  so  that  each  cubic  centimeter  represents 
1,000,000  dead  germs.  This  is  the  usual  dose,  though  it 
may  be  reduced  one-half  and  repeated  in  ten  or  twelve 
days. 

Administration. — The  dose  is  injected  subcutaneously 
in  the  arm  or  abdomen,  under  the  usual  antiseptic  pre- 
cautions. Following  the  injection  there  is  some  local 
reaction,  accompanied  by  redness,  swelling,  and  some 
pain  and  swelling  in  the  regional  lymphatic  glands. 
There  are  also  some  constitutional  disturbances,  varying 
from  a  slight  indisposition  to  chills  and  a  temperature 
of  100°  to  100.2°  F.,  with  general  aching  headache, 
nausea,  and  diarrhea.  They  all  disappear,  however, 


106  BACTERIOLOGY 

in  from  twelve  to  twenty-four  hours,  when  the  patient 
feels  as  well  as  ever. 

The  use  of  the  vaccine  is  becoming  a  routine  measure 
in  the  armies  of  the  world,  where  it  is  proving  most  suc- 
cessful, it  having  been  found  that  less  than  half  as  many 
vaccinated  men  have  the  disease  as  those  not  vaccinated, 
while  the  mortality  among  those  vaccinated  who  do  not 
contract  the  disease  is  less  than  one-fourth  that  among 
the  unvaccinated.  There  is  no  question  but  that  it  will 
soon  become  a  common  procedure  among  nurses,  doc- 
tors, travellers,  and  others  whose  duties  lay  them  liable 
to  infection. 

Tuberculin. — While  tuberculin  differs  in  its  constitu- 
ents from  the  other  bacterial  vaccines,  the  principle 
upon  which  it  acts  is  practically  the  same,  that  is,  the 
increase  of  the  opsonic  index  and  of  the  resistance  of 
the  individual  to  the  tubercle  bacillus  and  its  toxins. 

The  discovery  of  tuberculin  by  Koch  in  1890  antedates 
the  development  of  the  principle  of  opsonic  therapy  by 
many  years.  Unguided  by  subsequent  knowledge  of 
this  form  of  treatment,  the  early  advocates  of  tuberculin 
in  treatment  met  with  disaster  in  its  use,  and  its  employ- 
ment became  restricted  to  its  use  as  a  diagnostic  measure. 
The  knowledge  gained  in  the  use  of  bacterial  vaccines 
and  opsonic  index  has  enabled  us  to  use  tuberculin  with 
advantage  in  the  treatment  of  tuberculosis. 

The  method  of  employing  tuberculin  as  a  remedy  con- 
sists of  the  administration  in  the  beginning  of  very 


VACCINE  OR  OPSONIC  THERAPY  107 

minute  doses.  These  are  gradually  increased  at  inter- 
vals of  three  or  four  days,  with  the  object  of  increasing 
the  patient's  resistance  to  the  tubercle  germ  and  its 
products  until  complete  immunity  is  attained. 

Various  forms  of  tuberculin  are  designated,  depending 
upon  the  method  of  preparation  and  the  constituents 
retained. 

Old  Tuberculin  (Tuberculin  0.  T1.). — This  is  the  orig- 
inal tuberculin  of  Koch  and  contains  the  toxins  and  sol- 
uble secretions  of  cultures  of  tubercle  bacilli  grown 
on  glycerin  bouillon.  The  cultures  are  sterilized  by 
heat  and  the  germs  removed  by  nitration. 

New  Tuberculin  (Tuberculin  T.  R.). — This  is  pro- 
duced by  pulverizing  dried  tubercle  bacilli,  dissolving 
them  in  salt  solution  by  repeated  centrifuging,  and 
decanting  the  clear  liquid.  It  contains  the  entire  sub- 
stance of  the  germ. 

Koch's  belief  is  that  the  use  of  old  tuberculin,  consist- 
ing as  it  does  of  toxin  only,  produced  immunity  to  the 
toxin  alone,  while  the  proper  employment  of  the  new 
tuberculin  produced  immunity  to  both  toxin  and  germ, 
inasmuch  as  it  represents  the  entire  germ  and  not  the 
soluble  products  alone. 

The  Use  of  Tuberculin  in  Treatment. — As  will  be 
shown  in  the  study  of  tuberculin  in  diagnosis,  large  doses 
produce  a  reaction,  with  fever,  inflammation  at  the  site 
of  injection  and  the  site  of  the  lesion.  Such  reaction, 
if  profound  or  if  repeated,  will  do  great  injury.  There- 


108  BACTERIOLOGY 

fore,  in  the  use  of  this  agent,  great  care  must  be  exercised 
to  avoid  producing  a  reaction.  The  initial  dose  is, 
therefore,  placed  very  low.  Thus,  of  old  tuberculin  such 
a  dilution  is  used  as  will  give  -nriinF  nig-  in  each  2  minims. 
Two  minims  of  this  dilution  is  mixed  with  sterile  water 
and  injected  with  a  hypodermic  syringe  under  the  skin 
of  the  forearm  or  elsewhere,  where  it  may  be  watched 
for  local  reaction.  The  dose  is  increased  by  2  minims  at 
a  dose  every  four  to  eight  days  until  20  minims  are  in- 
jected, when  a  stronger  dilution  is  used,  one  containing 
•j-ffVr  mg.  to  each  2  minims.  After  the  injection  the  tem- 
perature, pulse,  and  respiration  are  carefully  watched 
for  signs  of  reaction.  Should  any  occur,  the  next  dose 
is  omitted  and  the  following  dose  reduced.  In  this  way 
the  patient's  tolerance  is  carefully  and  gradually  in- 
creased until  no  untoward  symptoms  follow  large  doses, 
i.  e.,  as  much  as  200  mg.  It  will  be  seen  that  the  tuber- 
culin treatment,  of  necessity,  must  occupy  an  extended 
period  of  tune,  and,  in  fact,  eight  months  to  a  year 
should  be  occupied  in  carrying  the  patient  through  the 
immunizing  process. 

Small-pox  Vaccine. — Vaccine  for  small-pox  was  orig- 
inated by  Jenner  in  1798.  He  observed  that  milkmaids 
who  had  pustules  upon  their  hands  resembling  those 
upon  the  cows'  udders  were  immune  to  small-pox.  It 
is,  therefore,  perhaps  the  oldest  known  application  of 
serum  therapy.  In  principle  it  differs  from  all  the  later 
biologic  remedies. 


VACCINE  OR  OPSONIC  THERAPY  109. 

The  principle  by  which  small-pox  vaccine  protects 
is  doubtless  that  of  a  modified  attack  of  the  disease 
through  a  diminution  of  the  virulence  of  the  causative 
germ  from  passage  through  an  unfavorable  host,  i.  e., 
the  cow.  In  other  words,  that  cow-pox  is  a  modified 
form  of  small-pox,  its  nature  and  virulence  having  been 
changed  by  the  resistance  and  general  character  of  the 
tissues  of  the  cow.  So  that  when  a  human  being  is  in- 
oculated with  vaccine  or  cow-pox,  he  has  a  mild  local 
disease  in  place  of  the  widespread  general  condition 
which  characterizes  small-pox.  This  mild  disturbance 
is  sufficient  to  establish  immunity  to  the  disease  for  a 
shorter  or  longer  period  of  time,  varying  from  three  or 
four  to  fifteen  or  twenty  years. 

The  causative  germ  of  small-pox  having  never  been 
isolated,  it  is  not  possible  to  determine  much  regarding 
the  mode  of  action  of  this  product,  but  years  of  invariable 
success  and  the  practical  wiping  out  of  small-pox  has 
established  its  value  beyond  quibble. 

Preparation. — In  the  preparation  of  small-pox  vaccine 
young  healthy  heifers  are  used.  They  are  carefully  ex- 
amined and  tuberculin-tested,  and  when  found  healthy 
are  shaved,  scrubbed  with  an  antiseptic,  and  inoculated 
with  cow-pox.  The  heifers  are  fed  on  milk  exclusively 
and  kept  in  separate  compartments.  When  the  pus- 
tules are  fully  developed  at  the  end  of  five  to  seven  days, 
their  contents  are  collected  under  strict  antiseptic  con- 
ditions. The  contents  of  the  pustules  are  mixed  with 


HO  BACTERIOLOGY 

glycerin,  macerated,  filtered,  and  preserved  in  sealed 
capillary  glass  tubes,  which  are  broken  and  their  contents 
ejected  by  means  of  a  small  rubber  bulb  when  used. 

Administration. — The  skin  of  the  forearm  or  thigh  is 
thoroughly  cleansed  with  soap  and  water,  followed  by  al- 
cohol. All  traces,  however,  of  alcohol  must  be  removed 
with  sterile  water  before  the  vaccine  is  applied.  Having 
thoroughly  cleansed  the  part,  a  small  abrasion  is  made 
either  with  a  small  needle  or  scarifier.  This  abrasion 
should  be  just  sufficient  to  cause  an  exudation  of  lymph, 
care  being  taken  to  avoid  drawing  blood,  which  would 
dilute  the  virus  and  wash  it  away,  thus  preventing  a 
successful  vaccination.  The  virus  is  then  ejected 
from  the  tube  upon  the  abrasion,  thoroughly  rubbed 
in  with  the  needle  or  scarifier,  and  allowed  to  dry  in  the 
air,  after  which  the  spot  should  be  protected  by  a  shield 
or  large  bunion  pad,  which  protects  it  from  rubbing  or 
injury,  but  at  the  same  time  permits  a  free  circulation  of 
air  to  the  part. 

Effects. — In  from  five  to  eight  days,  if  the  inoculation 
be  successful,  the  part  will  become  inflamed.  There 
will  occur  considerable  swelling,  with  pain  and  more  or 
less  swelling  and  tenderness  of  the  adjacent  lymphatic 
glands.  Some  fever  and  general  depression  are  also 
present.  At  the  site  of  inoculation  there  will  occur 
from  one  to  five  or  six  vesicles,  which  rapidly  coalesce 
and  become  pustular.  These  vesicles  are  umbilicated 
and  resemble  small-pox  pustules  in  a  minute  form.  The 


VACCINE  OR  OPSONIC  THERAPY  III 

vesic\e  dries  in  from  ten  to  twelve  days  and  the  scab 
slips  off,  leaving  a  typic  pitted  scar,  which  is  evidence  of 
successful  vaccination. 

Rabies  Vaccine  (Pasteur  Vaccine). — Pasteur  found 
that  the  infective  agent  or  its  toxin  in  rabies  was  located 
largely  in  the  spinal  cord  of  animals  having  the  disease, 
and  that  symptoms  of  the  disease  were  produced  in 
healthy  animals  by  the  introduction  of  portions  of  the 
spinal  cord  of  animals  having  the  disease.  He  also 
found  that  the  virulence  of  the  poison  was  diminished 
by  drying.  The  longer  the  infective  material  was  dried, 
the  less  its  virulence.  He  then  determined  that  im- 
munity to  the  disease  could  be  produced  by  injection 
of  emulsions  of  the  cord  containing  the  infective  agent, 
beginning  with  a  minute  dose  of  the  relatively  non- 
virulent  material  and  gradually  increasing  the  dose  and 
virulence  of  the  injected  material. 

Establishments  termed  Pasteur  institutes  are  located 
in  all  large  cities,  where  the  treatment  may  be  carried 
out.  The  vaccine  is  prepared  by  inoculating  rabbits 
beneath  the  dura  mater  with  rabic  material.  The 
animal  develops  rabies  in  six  days,  when  the  spinal  cord 
is  removed  and  dried  at  a  temperature  of  68°  F. 

A  piece  of  the  cord  which  has  been  dried  for  fourteen 
days  is  mixed  with  sterilized  veal  broth  and  injected 
beneath  the  skin  of  the  abdomen.  On  the  following  day 
material  from  a  cord  thirteen  days'  old  is  used,  and  so 
on,  each  day  using  material  a  day  younger,  until  fifteen 


112  BACTERIOLOGY 

injections  are  made.  To  be  of  value  the  immunizing 
process  must  be  given  before  the  onset  of  the  disease,  as 
soon  as  possible  following  the  bite  of  the  rabid  animal. 
As  the  incubation  period  of  hydrophobia  is  long,  extend- 
ing from  three  weeks  to  several  years,  sufficient  time  is 
usually  available  for  treatment. 

Recently,  enterprising  manufacturers  have  succeeded 
in  perfecting  a  plan  whereby  they  furnish  the  vaccine 
for  the  entire  treatment  of  a  case  upon  telegraphic 
notice,  shipping  the  varying  strengths  in  a  Caloris  bottle, 
which  protects  it  from  changes  of  temperature.  The 
physician  is  thus  enabled  to  give  the  treatment  at  the 
patient's  home,  saving  tune  and  the  necessity  of  a 
long  journey  to  some  distant  institute. 

It  should  be  remembered  that  this  is  a  purely  prophy- 
lactic measure,  the  organism  being  rendered  immune  to 
the  disease  during  the  period  of  incubation,  and  that 
after  the  onset  of  the  symptoms  the  treatment  is  useless. 
No  time  should,  therefore,  be  lost  following  a  bite  by  a 
suspected  animal  in  beginning  treatment,  either  at 
the  nearest  Pasteur  institute  or  by  means  of  the  vaccine 
prepared  and  forwarded  to  the  physician  by  the  dealer 
in  serums  and  antitoxins. 

Mode  of  Action. — While  it  is  impossible  to  say  with 
certainty  just  how  immunity  is  established  by  this  treat- 
ment, it  is,  without  doubt,  analogous  to  small-pox 
vaccination. 

A  modified  form  of  the  disease  is  produced  by  injec- 


VACCINE  OR  OPSONIC  THERAPY  113 

< 

tions  of  small  quantities  of  virus  whose  virulence  has 
been  attenuated  by  unfavorable  environment,  the  un- 
favorable environment  in  small-pox  being  the  cow;  in 
rabies,  the  drying  under  unfavorable  atmospheric  con- 
ditions. 

Effects. — It  is  not  possible  to  obtain  an  exact  estimate 
of  the  mortality  of  hydrophobia  before  the  advent  of  the 
vaccination  treatment,  but  it  is  placed  not  lower  than 
10  per  cent.  Under  the  vaccine  treatment  it  has  been 
lowered  to  much  less  than  i  per  cent.  Its  value  is, 
therefore,  unquestioned. 

Cholera  Vaccine  (Haffkine's  Cholera  Vaccine). — 
Like  small-pox  and  rabies  vaccination,  cholera  vaccina- 
tion consists  in  the  inoculation  with  attenuated  cultures 
of  the  germ  of  cholera.  Unlike  them,  however,  the 
germ  of  the  disease  has  been  identified  and  grown  arti- 
ficially for  the  production  of  the  vaccine.  Two  vaccines 
are  used,  a  weaker  and  a  stronger  one.  Injections  of 
the  virulent  germs  causes  excessive  tissue  destruction  at 
the  site  of  injection  unless  the  individual  has  been 
partially  immunized  by  the  injection  of  the  weaker  vac- 
cine. The  attenuated  culture  is  produced  by  growing 
the  cholera  bacteria  upon  agar  at  a  temperature  of  39°  C. 
in  a  current  of  air.  The  stronger  one  (and  here  the 
method  differs  radically  from  all  other  methods  of 
immunization)  is  produced  by  growing  the  germs  on 
living  guinea-pigs.  The  germs  from  the  peritoneal 
exudate  of  the  first  pig  inoculated  are  incubated  for  ten 


114  BACTERIOLOGY 

hours  at  a  temperature  of  35°  C.,  the  temperature  most 
suited  to  the  growth  and  development  of  the  organism. 
A  second  pig  is  then  inoculated  and  the  procedure  con- 
tinued until  a  culture  is  obtained  which  is  certainly 
fatal  to  a  pig  in  eight  hours.  A  slant  of  agar  is  com- 
pletely inoculated  with  this  virulent  culture  and  grown 
for  twenty-four  hours,  when  it  is  washed  off  with  broth 
and  diluted  up  to  8  c.c.  One  c.c.  constitutes  a  dose. 
Instead  of  an  attenuated  germ  we,  therefore,  have  one  of 
increased  virulence,  which,  were  it  not  for  the  partial 
immunity  already  effected  hi  the  individual  by  the 
weaker  vaccine,  would  most  certainly  prove  fatal.  The 
process  is  analogous  to  that  used  in  rendering  animals 
immune  to  anthrax. 

Administration. — The  vaccine  is  injected  into  the 
flank.  The  immunity  produced  by  each  injection  is 
attained  in  five  days,  so  the  second  injection  is  given  at 
the  end  of  that  time.  The  results  are  very  good,  but 
not  as  favorable  as  in  typhoid  vaccination. 

Recently,  Kolle  has  devised  a  method  of  vaccination 
in  which  the  cultures  are  killed  by  heat  before  injec- 
tion. The  results  of  this  method  of  vaccination  in  a 
recent  epidemic  of  cholera  in  Japan  have  been  even  more 
favorable  than  those  following  the  use  of  Haffkine's 
method  in  India. 


CHAPTER  XIV 

SERUM  DIAGNOSIS 

IN  addition  to  their  use  in  the  prevention  and  cure 
of  disease,  biologic  methods  are  of  great  value  in  diag- 
nosis in  certain  affections.  Among  the  curative  sera 
which  are  also  of  value  in  diagnosis,  tuberculin  holds 

first  place. 

THE  TUBERCULIN  TEST 

As  has  been  noted  in  the  consideration  of  tuberculin 
as  a  remedy  when  it  is  injected  into  an  individual  free 
from  tuberculosis,  there  occurs  no  disturbance  of  the 
vital  processes,  but  when  administered  in  any  consid- 
erable amount  to  one  affected  with  tuberculosis  certain 
disturbances  arise  which  are  referred  to  as  a  reaction. 

Tuberculin  Reaction. — The  symptoms  characteristic 
of  a  tuberculin  reaction  are  rise  of  temperature  to  one 
or  two  degrees  above  normal,  gastric  disturbance, 
headache,  malaise,  and  what  is  termed  the  local  reac- 
tion, consisting  of  redness,  swelling,  and  pain  at  the  site 
of  injection  and  at  the  site  of  the  disease.  One,  two,  or 
all  of  the  above  symptoms  may  be  present  in  varying 
degrees,  depending  upon  the  size  of  the  dose,  the  sus- 
ceptibility of  the  individual,  and  the  stage  of  the  disease. 

It  will  be  noted  that  in  the  use  of  tuberculin  in  treat- 

115 


n6  BACTERIOLOGY 

ment  the  dosage  is  kept  low  to  avoid  reaction,  gradually 
increasing  as  tolerance  is  established.  In  its  diagnostic 
use  quite  large  doses  are  used  for  the  purpose  of  bring- 
ing about  the  very  symptoms  it  is  sought  to  avoid  in  its 
employment  as  a  remedial  measure. 

Methods  of  Administering  the  Tuberculin  Test. — By 
Injection. — Old  tuberculin  is  used,  and  in  a  weak  patient 
the  dose  may  be  about  ^  mg.,  while  a  robust  one  should 
be  given  as  high  as  i  mg.  The  dose  is  injected  under 
the  skin  of  the  back,  observing  the  usual  antiseptic 
precautions.  Should  no  rise  of  temperature  occur, 
another  injection  of  double  the  amount  of  the  first  dose 
is  given  on  the  third  day.  In  robust  patients  even 
larger  doses  may  be  given,  such  as  5  or  10  mg.  at  the 
second  or  third  dose,  when,  if  no  reaction  occurs,  the 
patient  may  be  considered  free  from  active  or  progress- 
ive tuberculosis.  A  very  slight  rise  of  temperature,  if 
accompanied  by  a  local  reaction,  should  be  considered 
positive. 

Cutaneous  Reaction,  Von  Pirquet's  Test. — This  form 
of  the  tuberculin  test  consists  of  the  application  of 
tuberculin  to  the  skin  by  scarification.  The  inner  side 
of  the  forearm  is  washed  with  ether.  Two  drops  of  old 
tuberculin  are  dropped  upon  the  arm  about  4  inches 
apart.  The  skin  is  then  scarified  first  between  the  two 
drops,  then  within  each  of  the  drops  with  a  special  scari- 
fier furnished  for  the  purpose,  the  amount  of  abrasion 
being  sufficient  to  form  a  scab,  but  under  no  circum- 


SERUM  DIAGNOSIS  117 

stances  great  enough  to  draw  blood.  A  small  tuft  of 
cotton  is  applied  to  each  drop  to  prevent  its  flowing 
away.  The  center  scarification  serves  the  purpose  of 
a  control  with  which  to  compare  the  spots  to  which 
the  tuberculin  is  applied. 

The  reaction  is  considered  positive  when  the  tuber- 
culin spots  give  a  hyperemic  zone  of  4  to  6  mm.  with 
a  papule  in  the  center.  From  such  a  feeble  reaction  the 
reaction  may  vary  in  intensity  to  the  production  of 
numerous  papules  with  considerable  edema  and  redness, 
persisting  for  several  hours. 

Ophthalmo-reaction,  Wolff-Eisner  and  Calmette  Test. 
— A  drop  of  dilute  tuberculin  is  instilled  in  the  eye.  A 
positive  reaction  is  characterized  by  congestion  of  the 
palpebral  conjunctiva  and  caruncle,  with  more  or  less 
serofibrinous  exudate.  The  reaction  disappears  in 
from  twenty-four  to  forty-eight  hours. 

The  Moro  Reaction. — This  is  a  cutaneous  reaction 
produced  by  applying  a  tuberculin  ointment  to  the  un- 
broken skin. 

A  concentrated  ointment  of  tuberculin  in  anhydrous 
lanolin  is  used,  and  a  small  amount  energetically  rubbed 
into  the  skin  of  the  abdomen  or  breast  for  about  a  minute. 

A  positive  reaction  is  characterized  by  the  appearance 
in  from  a  few  to  twenty-four  or  forty-eight  hours  of  a 
granular  or  papular  eruption  of  varying  intensity,  ac- 
companied by  more  or  less  itching,  and  lasting  from  a  few 
hours  to  several  days.  Of  these  several  local  tests,  the 


Il8  BACTERIOLOGY 

cutaneous  reaction  of  Von  Pirquet  and  of  Moro  are  the 
safest  and  most  dependable.  They  are  especially  accu- 
rate in  children.  The  ophthalmo-reaction  is  less  reliable 
and  is  attended  with  some  danger  to  the  eye,  especially 
should  there  exist  some  previous  inflammatory  condition 
of  that  organ. 

It  may  be  noted  in  passing  that  the  tuberculin  test 
affords  a  most  efficient  means  of  recognizing  tuberculosis 
hi  cattle,  and  is,  therefore,  of  signal  importance  in  efforts 
to  obtain  a  tuberculosis-free  milk-supply  for  cities  and 
institutions. 

THE  VIDAL  TEST  FOR  TYPHOID  FEVER 

The  Widal  (or  agglutination)  test  for  typhoid  fever 
has  been  referred  to  before  in  this  work.  It  depends 
upon  the  presence  in  the  blood  of  a  typhoid  patient  at  a 
certain  stage  of  the  disease  of  substances  termed  agglu- 
tinins,  which  when  brought  in  contact  with  living  ty- 
phoid bacilli  cause  them  to  clump  together  and  cease  their 
ambulatory  movements.  It  is  evident,  therefore,  that 
the  infection  must  have  been  present  a  certain  length 
of  time  for  the  Widal  test  to  be  positive,  that  is,  until 
sufficient  time  has  elapsed  for  the  agglutinins  of  the 
typhoid  germ  to  have  been  elaborated  in  the  blood  of  the 
patient,  or  the  Widal  test  will  be  negative.  We  find, 
therefore,  that  the  test  is  of  no  practical  value  until  after 
the  first  week  of  the  infection.  The  test  is  also  uncertain 
because  of  the  fact  that  the  blood  of  many  normal  per- 


SERUM  DIAGNOSIS  119 

sons  possesses  the  agglutinating  property  for  typhoid 
germs.  It  is  less  marked,  however,  than  in  those  in- 
fected with  typhoid,  and,  therefore,  in  making  the  test 
the  blood-serum  is  diluted  to  about  i  to  50,  when  the 
agglutinating  power  (of  any  but  the  typhoid  blood)  is  too 
attenuated  to  manifest  itself. 

Method  of  Application. — The  lobe  of  the  ear  having 
been  cleaned  with  bichlorid,  lysol,  or  other  antiseptic, 
followed  by  sterile  water,  a  deep  puncture  is  made  with 
a  sterile  needle  or  other  pointed  instrument.  A  small 
amount  of  blood  is  collected  either  in  a  capillary  tube 
or  upon  a  sterile  cover-glass.  The  blood  or,  preferably, 
the  serum  portion  is  diluted  with  normal  salt  solution  or 
broth  to  i  to  25,  then  a  drop  of  this  dilution  is  mixed 
with  an  equal  amount  of  young  vigorous  typhoid  germs 
from  a  broth  culture,  placed  in  hanging-drop  beneath 
the  microscope,  and  observed. 

Should  the  test  be  positive,  in  from  one-half  to  two 
hours  the  bacilli  will  be  seen  to  clump  together  into 
masses  and  lose  their  motility.  The  test  may  be  made 
without  the  use  of  the  microscope  by  mixing  the  culture 
and  serum  in  a  test-tube,  when  at  the  end  of  the  usual 
time  a  flocculent  precipitate  will  be  observed  to  form  in 
the  mixture. 

TYPHOID  OPHTHALMO-REACTION 

This  test  is  similar  to  the  tuberculin  ophthalmo- 
reaction.  A  solution  of  J  to  J  mg.  of  "typho-protein," 


120  BACTERIOLOGY 

an  extract  of  typhoid  bacilli,  is  mixed  with  a  drop  of 
water  and  instilled  into  the  conjunctival  sac  of  a  patient 
suspected  of  having  typhoid  fever.  If  typhoid  be  present 
a  typic  reaction  occurs,  which  is  characterized  by  hyper- 
emia  and  injection  of  the  palpebral  conjunctiva  of  the 
lower  lid  and  the  caruncle. 

In  75  cases  of  typhoid  fever  a  positive  reaction 
occurred  in  71.  The  reaction  takes  place  within  from 
one  to  two  and  a  half  hours,  and  persists  for  from  thirty- 
six  to  forty-eight  hours.  The  reaction  causes  no  discom- 
fort and  appears  to  be  without  danger.  It  is  of  recent 
development  and  has  not  yet  been  widely  used,  but  it 
promises  to  be  one  of  the  most  accurate  and  least  com- 
plicated of  any  of  the  later  diagnostic  measures. 

THE  WASSERMANN  TEST  FOR  SYPHILIS 

This  test  depends  upon  hemolysis  and  the  so-called 
deviation  and  fixation  of  complement.  The  process  is 
most  too  complicated  for  practical  demonstration  in  a 
work  of  this  character,  but  an  endeavor  will  be  made  to 
give  such  an  exposition  of  the  subject  as  will  enable 
one  to  understand  the  principle  involved  in  the  test. 

We  have  learned  that  when  the  blood  of  an  animal 
of  one  species  is  injected  into  an  animal  of  a  different 
species,  the  blood  of  the  animal  injected  acquired  power 
of  hemolysis  (i.  e.,  ability  to  destroy  the  corpuscles)  for 
the  blood  of  the  species  from  whence  the  injected  blood 
came. 


SERUM  DIAGNOSIS  12 1 

If  this  hemolytic  serum  he  heated,  it  loses  its  hemolytic 
power,  but  it  may  be  restored  by  the  addition  of  a  small 
amount  of  normal  serum  from  some  animal  of  the  same 
species.  Therefore,  if  red  blood-cells  be  mixed  with 
their  inactivated  hemolytic  serum  (i.  e.,  their  hemolytic 
serum  which  has  been  heated),  and  normal  serum  from 
some  animal  of  the  same  species  as  that  from  which  the 
hemolytic  serum  came  be  added,  hemolysis  of  the  red 
cells  will  take  place.  Should  there  be  immune  bodies 
for  a  certain  germ  in  the  added  serum,  the  hemolysis 
will  occur  just  the  same.  If,  however,  there  be  immune 
bodies  for  a  certain  germ  present,  and  a  pure  culture  of 
that  germ  be  added  to  it  before  it  is  mixed  with  the  red 
cells  and  their  inactivated  hemolytic  serum,  the  germs 
become  attached  to  the  immune  bodies,  so  fixing  the 
constituents  of  the  serum  as  to  prevent  its  acting  upon 
the  inactivated  hemolytic  serum  to  restore  its  hemolytic 
power.  Hemolysis,  therefore,  does  not  occur. 

In  the  Wassermann  test  for  syphilis,  red  blood-cells 
of  the  sheep  are  mixed  with  human  serum  which  has 
been  rendered  hemolytic  for  them  and  inactivated  by 
heat.  The  addition,  now,  of  human  serum  from  what- 
ever source  would,  of  course,  activate  the  inactivated 
serum,  and  hemolysis  of  the  red  cells  would  occur.  The 
serum  which  is  to  be  tested  for  syphilis  is  mixed  with 
an  extract  of  syphilitic  fetal  liver,  pure  cultures  of  the 
syphilitic  germ  being  unavailable,  and  then  added  to  the 
mixture  of  inactivated  hemolytic  serum  and  red  cells. 


123  BACTERIOLOGY 

Should  there  be  no  syphilis  present  in  the  individual  and, 
therefore,  no  syphilitic  antibodies  in  his  blood,  the  ad- 
dition of  the  germs  from  the  syphilitic  liver  will  not  affect 
the  serum  in  the  least,  and  it  will  proceed  to  activate  the 
inactivated  hemolytic  serum,  which  will  then  destroy 
the  red  cells  by  hemolysis.  The  test  is  then  said  to  be 
negative. 

Should  syphilis,  however,  be  present,  the  syphilitic 
antibodies  will  be  bound  to  the  syphilitic  germs  in  the 
fetal  liver  extract,  and  the  serum  thus  rendered  unable 
to  activate  the  hemolytic  serum  in  the  mixture.  Hemo- 
lysis would,  therefore,  not  take  place,  and  the  test  would 
be  positive. 


CHAPTER  XV 

ANAPHYLAXIS 

ANY  discussion  of  serum  therapy  would  be  incom- 
plete without  reference  to  the  phenomenon  of  anaphy- 
laxis.  The  name  "anaphylaxis"  is  from  the  German, 
and  signifies  "against  protection." 

It  has  been  found  that  the  introduction  into  the  blood 
of  an  animal  of  certain  protein  or  albuminous  substances, 
such  as  blood-serum,  bacterial  proteins,  egg-white, 
milk,  etc.,  will  produce  in  the  animal  injected  a  condi- 
tion of  hypersusceptibility,  so  that  when  another  in- 
jection of  the  same  substance  is  made  after  a  definite 
length  of  time  has  elapsed  for  the  condition  to  develop, 
symptoms  of  poisoning  occur  immediately  following 
the  injection.  The  symptoms  characterizing  this  con- 
dition are  weakness,  difficult  respiration  or  asthmatic 
paroxysms,  weakened  heart's  action,  and  even  death. 

The  explanation  of  this  condition  is  that  when  a 
foreign  protein  is  introduced  into  the  blood,  antibodies 
for  that  particular  protein,  which  are  either  present  at 
the  time  or  are  soon  formed,  begin  the  destruction  of 
such  foreign  proteins  by  decomposition  or  splitting  up 
into  simpler  forms  of  matter. 

123 


124  BACTERIOLOGY 

At  a  certain  stage  of  decomposition  of  protein  material 
poisonous  products  are  formed.  The  process  does  not 
stop  here,  however,  but  continues,  and  the  poisonous 
products  are  further  split  up  into  non-poisonous  sub- 
stances. Should  a  large  amount  of  such  poisonous 
substances  be  liberated  at  one  time,  they  might  do  great 
damage  to  the  organism  before  they  could  be  further 
decomposed  and  rendered  inert.  Practically  the  same 
process  occurs  in  gastric  and  intestinal  digestion,  but 
the  poisonous  products  are  easily  further  decomposed 
and  rendered  inert  before  they  are  absorbed  into  the 
circulation.  Should  anything  occur  to  stop  digestion  at 
this  point  the  poisons  may  be  absorbed,  and  cause 
a  condition  of  auto-intoxication  which  may  be  looked 
upon  as  analogous  to  anaphylaxis. 

It  is  probable  that  upon  the  introduction  of  the  foreign 
proteins  of  horse-serum,  in  antitoxin,  for  instance,  there 
are  but  few  antibodies  for  that  particular  substance 
present.  Its  destruction  or  breaking  up  takes  place 
slowly  and  small  amounts  of  the  poisonous  products  of 
decomposition  are  liberated  at  a  time,  so  that  they  are 
soon  neutralized  without  having  done  any  injury. 
During  this  process  or  following  the  introduction  of  the 
foreign  protein,  large  amounts  of  antibodies  for  the  sub- 
stance are  formed.  If  now,  at  the  height  of  the  develop- 
ment of  these  antibodies,  usually  in  about  eight  to  ten 
days  from  the  first  injection,  another  injection  of  the 
same  serum  be  given,  it  is  decomposed  so  rapidly  that  a 


ANAPHYLAXIS  125 

large  amount  of  the  toxic  element  is  produced  at  once, 
and  the  injurious  effects  of  anaphylaxis  are  manifest. 

It  is  quite  likely  that  many  of  the  symptoms  of  in- 
fection heretofore  attributed  to  toxins  are  due  to  ana- 
phylaxis, and  the  poisons  generated  in  the  decomposi- 
tion of  the  protoplasm  of  the  germs  by  antibodies  of  the 
infected  organism. 

The  practical  lesson  of  this  matter  then  is  that  great 
care  should  be  exercised  in  the  administration  of  the 
various  antitoxins  and  serums  to  avoid  the  production 
of  anaphylaxis.  It  would  be  better,  therefore,  to  ad- 
minister large  initial  doses  of  serum  rather  than  small 
doses  which  must  needs  be  repeated.  When  a  second 
dose  of  serum  becomes  necessary,  it  should  follow  the 
first  at  as  short  an  interval  as  possible,  so  that  time  shall 
not  have  elapsed  for  the  development  of  hypersuscep- 
tibility.  If  it  be  known  that  one  has  had  a  previous 
administration  of  a  particular  serum  at  some  former  ill- 
ness, another  administration  of  that  serum  should  be 
undertaken  with  caution.  A  very  minute  dose  should 
be  given  and  the  patient  closely  watched  for  signs  of 
anaphylaxis.  Should  these  not  arise  within  an  hour  or 
so,  a  full  dose  may  then  be  given. 


PATHOLOGY 


PATHOLOGY  is  the  science  which  treats  of  disease,  its 
causes,  symptoms,  and  results. 

Disease  is  a  condition  of  a  living  organism  character- 
ized by  abnormality  in  structure,  in  function,  or  in  both 
combined. 

CHAPTER  XVI 
ETIOLOGY  OF  DISEASE 

THE  causes  of  disease  are  numerous.  As  we  have 
already  learned,  bacteria  and  their  toxins  are  the  cause 
of  diseases,  and  in  our  daily  combat  with  these  minute 
agencies  we  are  prone  to  lose  sight  of  the  other  innumer- 
able causes  of  abnormality  of  structure  and  function 
which  exist  throughout  nature. 

Traumatism  is  the  name  given  to  mechanical  injury. 
Besides  the  ordinary  wounds,  bruises,  contusions  of  the 
soft  tissues,  and  fractures  of  bones,  gradual  pressure 
may  cause  atrophy,  and  if  prolonged  or  of  increased 
intensity  may  result  in  necrosis  or  gangrene. 

Heat. — Local  excess  of  heat  produces  various  lesions, 
depending  upon  its  intensity  and  length  of  application, 
from  simple  hyperemia,  vesicle  formation,  to  charring 

126 


ETIOLOGY  OF  DISEASE  127 

and  local  necrosis,  followed  by  profound  inflammation. 
Burns  involving  large  surfaces,  one-third  or  more  of 
the  body  surface,  often  cause  death,  doubtless  through 
the  production  of  poisonous  products  of  tissue  and  blood 
destruction.  General  high  temperature  leads  to  heat- 
stroke, sunstroke,  insulation,  or  heat  exhaustion.  In 
these  conditions  there  may  occur  hyperemia  and  edema 
or  even  inflammation  of  the  meninges,  which  lesions  are 
doubtless  due  to  the  production  within  the  body  of 
poisonous  substances  the  result  of  disturbed  metabolic 
processes. 

Cold. — Exposure  to  extreme  degrees  of  cold  gives  rise 
to  lesions  similar  to  those  produced  by  heat.  Locally, 
there  are  produced  by  excessive  low  temperature  vesic- 
ulation  and  necrosis,  similar  to  burns.  In  exposure  to 
cold  the  extremities  are  first  to  suffer.  The  blood  being 
driven  inward  to  maintain  the  internal  bodily  heat, 
local  anemia  occurs,  followed  by  vascular  paralysis, 
with  hyperemia  and  necrosis.  Prolonged  exposure  to 
general  low  temperature  leads  to  gradual  obtunding  of 
sensibility  and  coma. 

Cold  was  formerly  believed  to  be  the  cause  of  coryza, 
pharyngitis,  bronchitis,  and  similar  conditions  referred 
to  by  the  term  "catching  cold."  It  is  now  known  to  be 
but  a  predisposing  factor,  the  real  cause  being  infection 
with  certain  micro-organisms,  the  effect  of  cold  doubt- 
less being  to  lower  the  resistance  and  natural  protective 
properties  of  the  body. 


128  PATHOLOGY 

Insufficient  Air. — A  sufficient  supply  of  fresh  air  is 
necessary  to  the  proper  oxygenation  of  the  blood  and  the 
maintenance  of  health. 

Asphyxia. — If  the  insufficiency  be  great,  asphyxia, 
a  condition  of  cyanosis,  depression,  and  stupor  occur. 

Suffocation. — Complete  lack  of  air  causes  suffocation 
and  death.  '  * 

Poisons. — Definition. — Any  substance  which  intro- 
duced into  the  living  organism  direct  tends  to  destroy 
the  life  or  impair  the  health  of  that  organism. 

The  effects  of  poisons  depend  upon  the  nature  of  the 
poison,  the  dose,  and  the  nature  of  the  individual. 
Tolerance  or  immunity  may  be  produced  by  repeated 
ingestion  of  poisons. 

Corrosive  Poisons,  Escharotics,  Caustics. — Such  poi- 
sons, which  are  exemplified  by  various  acids,  alkalis, 
mineral  poisons,  nitrate  of  silver,  etc.,  cause  destruction 
of  the  cells  with  which  they  come  in  contact  by  abstrac- 
tion of  water  and  coagulation  of  the  albuminous  con- 
tents of  the  cell.  They  cause  local  lesions  similar  to 
burns,  with  necrosis,  sloughing,  and  surrounding  inflam- 
mation. 

Organic  poisons  are  those  which  enter  the  blood  and 
cause  extensive  lesions  to  various  organs  of  the  body, 
as  the  kidneys,  liver,  gastro-intestinal  mucous  mem- 
brane, heart  muscles,  blood-vessels,  etc.  Such  poisons 
are  lead,  arsenic,  phosphorus,  and  mercury. 

Toxins  of  Bacteria. — As  we  have  seen,  the  toxins  of 


ETIOLOGY  OF  DISEASE  129 

bacteria  cause  various  lesions  throughout  the  body. 
Some  act  as  organic  poisons,  causing  degeneration  of 
heart  muscles  or  kidney  structure,  as  in  diphtheria  and 
scarlet  fever;  while  others,  as  in  tetanus,  act  as  nerve 
poisons. 

Venom  of  Serpents  and  Insects. — The  poisons  of  snakes 
and  insects  produce  both  local  and  general  lesions. 
Locally,  they  give  rise  to  inflammation  and  necrosis,  and, 
entering  the  blood,  they  act  as  organic  poisons,  causing 
extensive  destruction  of  internal  organs  and  the  blood 
itself. 

9 


CHAPTER  XVII 

DISORDERS  OF  NUTRITION  AND  METABOLISM 

Foods  are  those  substances  with  which  living  organ- 
isms repair  tissues  consumed  in  the  wear  and  tear  of  life, 
and  furnish  the  heat  and  energy  for  the  vital  processes. 

Inanition  and  Starvation. — Lack  of  food  causes  a 
diminution  of  energy  and  weakness  followed  by  loss  of 
weight,  as  the  various  tissues  of  the  body  are  appropri- 
ated to  maintain  heat  and  energy.  The  fat  and  muscles 
are  consumed  first,  then  the  tissues  of  the  liver,  bones, 
and  heart.  Such  a  condition  may  occur  either  from  lack 
of  food  or  from  inability  to  digest  and  appropriate  food, 
as  in  cancer  of  the  stomach  or  intestines. 

Overfeeding. — An  increased  ingestion  of  food  in  per- 
sons of  great  digestive  capacity  may  cause  various  dis- 
orders, first  among  which  may  be  mentioned  obesity  or 
increase  of  the  fatty  tissues  of  the  body.  Such  increase, 
if  deposited  about  the  heart  or  within  the  heart  muscles, 
may  cause  death. 

Overfeeding  necessarily  is  a  relative  matter,  as  great 
energy  and  muscular  exertion  must  call  for  more  food  in 
the  same  individual  than  comparative  quiet  and  lack 
of  exercise.  Besides  fatty  deposits  in  the  heart,  kidneys, 
and  blood-vessels,  overfeeding  leads  to  the  condition 

130 


DISORDERS  OF  NUTRITION  AND  METABOLISM     131 

termed  atheromatous  degeneration  of  the  blood-vessels, 
a  condition  in  which  the  blood-vessels  become  hardened 
and  loose  their  elasticity,  thus  increasing  the  blood- 
pressure.  The  increased  pressure  upon  the  weakened 
walls  of  the  vessels  frequently  causes  rupture  of  the  walls, 
especially  of  the  small  vessels  of  the  brain,  the  resulting 
condition  being  known  as  apoplexy.  Other  results  of 
overfeeding  are  auto-intoxication  from  a  retention  of 
partially  oxidized  products  of  metabolism.  Of  these, 
gout  is  an  example.  In  gout  there  occur  deposits  of 
urates  about  the  joints,  with  consequent  inflammatory 
reaction. 

Glycosuria  and  Diabetes. — The  carbohydrate  food- 
supply  is  utilized  in  part  by  being  transformed  by  the 
liver  into  a  peculiar  form  of  sugar,  called  glycogen,  which 
is  stored  up  in  the  liver  cells  and  muscles  of  the  body  and 
gradually  discharged  into  the  blood  as  needed.  Oc- 
casionally, when  the  supply  of  carbohydrate  food  is  ex- 
cessive, more  glycogen  is  produced  than  can  be  stored  up 
in  the  muscles  and  liver,  and  the  excess  is  discharged 
through  the  kidneys.  Such  a  condition  is  termed 
glycosuria. 

Diabetes. — This  is  a  disease  characterized  by  an  in- 
creased excretion  of  urine  containing  sugar.  The  cause 
of  this  disorder  is  not  known,  but  it  seems  to  be  con- 
nected with  diseases  of  the  pancreas.  Removal  of  the 
pancreas  in  animals  causes  glycosuria.  Just  how  this  is 
brought  about  is  not  clear.  The  essential  facts  of  the 


132  PATHOLOGY 

condition  are  that  the  body  is  not  able  to  appropriate 
the  carbohydrates  for  the  production  of  energy,  and 
the  unused  glycogen  passes  off  through  the  kidneys. 
The  proteins  of  the  tissues  are  then  drawn  on  for  the 
production  of  energy,  their  destruction  leading  to  emaci- 
ation, acid  intoxication,  coma,  and  death. 

Fever. — Definition. — Fever  is  that  condition  in  which 
the  temperature  of  the  body  is  above  98.6°  F.  In 
health  there  is  a  constant  relation  of  heat  production  to 
heat  dissipation,  regulated  by  the  nervous  system.  In 
sickness  the  relation  is  disturbed,  due  either  to  increased 
heat  production  or  to  decreased  radiation  or  dissipation, 
or  to  greater  increase  of  production  than  increase  in 
dissipation. 

Causes  of  Fever. — The  primary  causes  of  fever  may 
vary  greatly,  but  they  probably  all  depend  upon  the 
liberation  into  the  blood  of  toxic  substances.  It  is  the 
toxins  of  bacteria  that  give  rise  to  elevation  of  tempera- 
ture in  the  various  infectious  diseases,  and  it  is  well 
known  that  many  injuries  to  the  tissues  give  rise  to  the 
production  of  toxic  substances,  either  as  the  product  of 
disordered  metabolism  or  of  degeneration  of  tissue  cells. 
These  toxic  substances  may  so  act  upon  the  nervous  sys- 
tem as  to  cause  elevation  of  temperature.  Likewise, 
toxic  substances  occur  as  the  result  of  perverted  digestive 
action  and  decomposition  in  the  intestinal  tract.  This 
is  a  frequent  cause  of  elevated  temperature  in  infants 
and  children. 


DISORDERS  OF  NUTRITION  AND  METABOLISM     133 

It  is  probable  that  fever  is  a  conservative  process,  and 
that  in  some  way  it  has  to  do  with  the  destruction  and 
elimination  from  the  body  of  the  toxic  material  causing 
it.  That  most  pathogenic  bacteria  are  unfavorably 
influenced  by  high  temperature  is  well  known,  but 
whether  the  temperature  of  the  body  in  fever  is  suf- 
ficiently high  to  have  any  marked  influence  upon  the 
bacteria  themselves  is  not  as  yet  proved.  There  is 
little  doubt,  however,  that  such  increased  temperature 
has  to  do  with  the  destruction  of  the  toxic  products 
of  bacteria. 


CHAPTER  XVIII 
DISTURBANCES  OF  CIRCULATION 

Hypostatic  Congestion. — In  extreme  weakness  of  the 
heart  the  blood  tends  to  collect  in  the  dependent  por- 
tions of  the  body.  This  condition  is  known  as  hypo- 
static  congestion.  It  occurs  in  low  fevers  and  frequently 
results  in  the  formation  of  ulcerations  or  bed-sores. 

Local  Hyperemia. — This  is  a  condition  of  increased 
amount  of  blood  in  any  part  of  the  body.  It  may  be 
either  active  or  passive.  Active  hyperemia  or  arterial 
hyperemia  may  be  functional,  as  in  the  ovaries  at  the 
menstrual  period,  or  pathologic,  when  it  is  due  to  dila- 
tation of  the  arteries  from  vasomotor  activity  or  from 
injury  and  weakening  of  the  walls  of  the  arteries.  The 
hyperemic  area  is  bright  red  in  color,  the  temperature  is 
elevated,  and  there  is  slight  swelling. 

Passive  hyperemia,  or  venous  hyperemia,  is  due  to 
obstruction  of  the  outflow  of  the  blood  from  the  veins. 
The  obstruction  may  be  due  to  thickening  of  the  vessel 
walls,  to  tumors,  or  to  thrombi  within  the  vessels. 
Areas  the  seat  of  passive  hyperemia  are  dark  red  in 
color  (cyanotic)  and  of  lowered  temperature,  followed 
soon  by  swelling  and  edema. 

134 


DISTURBANCES  OF  CIRCULATION  135 

Local  anemia,  or  ischemia,  is  the  condition  in  which  a 
part  of  the  body  contains  less  than  the  normal  amount  of 
blood.  Pressure  is  the  most  frequent  cause  of  this  con- 
dition, though  an  artery  may  be  obstructed  by  sclerosis 
of  the  vessel  walls  or  by  emboli  or  thrombi.  The  anemic 
area  is  pale,  reduced  in  size  and  temperature,  and  func- 
tionally less  active. 

Hemorrhage  is  the  escape  of  blood  from  the  blood- 
vessels. It  is  termed  arterial,  venous,  or  capillary,  ac- 
cording to  the  vessel  from  which  the  flow  of  blood  occurs. 
It  may  occur  by  diapedesis  or  extravasation  through 
an  intact  vessel  wall  or  by  rupture  of  the  walls  of  the 
vessel. 

Diapedesis. — Under  certain  abnormal  conditions  red 
blood-corpuscles  may  pass  through  an  intact  vessel  wall 
and  collect  in  the  tissues.  This  is  known  as  diapedesis. 
Altered  states  of  the  vessel  walls  and  of  the  blood  itself 
induced  by  infectious  diseases  give  rise  to  diapedesis. 
The  small  collections  of  blood  in  the  tissues  are  called 
petechiae.  The  petechiae  of  purpura  and  the  rose  spots 
of  typhoid  fever  are  examples  of  diapedesis. 

Emigration. — Under  normal  conditions  a  certain 
number  of  white  blood-corpuscles  escape  from  the  cap- 
illaries and  wander  about  in  the  tissues;  this  is  a  normal 
process  and  is  known  as  emigration. 

Hemorrhage  from  rupture  of  the  vessel  walls  may  occur 
from — 

(i)  Traumatism,  knife  wounds,  crushing  injuries,  etc. 


136  PATHOLOGY 

(2)  Disease  of  vessel  walls,  atheroma,  aneurysm,  or 
ulceration,  as  in  phthisis. 

(3)  Hemophilia,  a  hereditary  tendency  to  spontaneous 
hemorrhages. 

Classification  of  Hemorrhages: 

Epistaxis,  hemorrhage  from  the  nose. 

Hemoptysis,  hemorrhage  from  the  lungs. 

Hematemesis,  hemorrhage  from  the  stomach, 

Enterorrhagia,  hemorrhage  from  the  bowel. 

Metrorrhagia,  hemorrhage  from  the  uterus  between 
menstrual  periods. 

Menorrhagia,  hemorrhage  from  the  uterus,  profuse  at 
menstrual  period. 

Hematuria,  hemorrhage  from  the  urinary  organs. 

Embolism  is  the  process  in  which  foreign  bodies  are 
carried  into  the  blood-stream  and  become  lodged  in 
the  smaller  capillaries,  through  which  they  are  not 
able  to  pass  because  of  their  size.  The  objects  thus 
deposited  are  termed  emboli. 

Kinds  of  Emboli. — Dust,  portions  of  iron,  coal,  marble, 
etc.;  portions  of  blood-clot  or  thrombi;  cells  from  liver 
or  placenta,  tumor-cells  or  masses;  fat-emboli  in  frac- 
ture of  bones;  air-emboli  in  wounds  of  large  veins;  bac- 
teria and  other  parasites. 

Results  of  Embolism. — Death  may  occur  from  occlu- 
sion of  the  coronary  arteries  or  cerebral  vessels.  In 
smaller  vessels  the  results  depend  upon  the  nature  of 
the  emboli.  If  bacteria  or  septic  material,  a  new 


DISTURBANCES  OF  CIRCULATION  137 

septic  foci  occurs.  If  aseptic,  they  may  form  an 
infarct. 

Infarct. — This  term  is  applied  to  a  wedge-shaped  area 
of  tissue  which  has  been  deprived  of  its  nutrition  by 
occlusion  of  an  end  artery,  that  is,  an  artery  having 
little  or  no  arterial  anastomosis. 

White  Infarct.—  This  form  of  infarct  is  due  to  anemia 
or  to  coagulation  necrosis. 

Hemorrhagic  Infarct. — In  some  cases  the  anemic  area 
becomes  filled  with  blood  from  back  flow  from  the  veins 
or  from  capillary  anastomosis;  the  condition  is  then 
known  as  hemorrhagic  or  red  infarct. 

Thrombosis  is  the  process  of  coagulation  of  blood 
within  the  heart  or  vessels.  The  clot  thus  formed  is 
called  a  thrombus.  Blood  will  not  clot  within  the  vessels 
unless  one  or  more  of  the  following  causes  be  present: 
First,  slowing  of  the  blood-current,  as  in  exhaustive 
illnesses  and  fevers,  or  from  pressure  upon  the  vessel 
walls  from  tumors  or  growths;  second,  changes  in  the 
vessel  walls,  as  from  injuries,  atheroma,  or  inflamma- 
tion; third,  alteration  in  the  blood,  which  increases  the 
tendency  toward  coagulation. 

Results  of  Thror  basis. — Collateral  circulation  may  be 
established,  when  no  results  will  follow,  or,  no  collateral 
circulation  being  established,  degeneration  and  necrosis 
may  occur.  Organization  may  occur  and  the  thrombus 
be  converted  into  connective  tissue.  Simple  softening 
may  occur  and  portions  of  the  thrombus,  becoming 


138  PATHOLOGY 

detached,  form  emboli.  Purulent  softening  may  occur, 
followed  by  infectious  emboli  and  pyemia. 

Edema  or  dropsy  is  that  condition  in  which  there  is 
an  excessive  amount  of  fluid  in  the  tissues.  The  most 
important  causes  of  edema  are:  Increased  blood-press- 
ure, the  result  usually  of  heart  disease  or  the  pressure  of 
tumors  upon  the  veins,  etc.  The  fluid  constituents  of 
the  blood  are  thus  forced  through  the  vessel  walls  into 
the  tissues.  Another  cause  is  found  in  increased  per- 
meability of  the  vessel  walls  in  Bright's  disease,  which 
causes  extensive  changes  in  the  vessel  walls.  The  tis- 
sues the  seat  of  edema  present  a  pale,  swollen  appear- 
ance, of  doughy  feeling,  and  upon  pressure  an  indenta- 
tion remains  behind. 

Ascites. — Edema  of  the  abdominal  cavity  is  known  as 
ascites. 

Hydrothorax  is  the  term  applied  to  edema  of  the  thor- 
acic cavity. 

Inflammatory  edema  refers  to  edema  around  an  in- 
flamed area. 


CHAPTER  XIX 
RETROGRADE  PROCESSES 

Atrophy. — This  is  a  condition  in  which  a  fully  devel- 
oped organ  or  part  undergoes  a  uniform  diminution  in 
size,  due  to  a  disappearance  of  the  elemental  cells  of  the 
organ  or  part. 

Hypoplasia  is  a  condition  in  which  from  lack  of  devel- 
opment an  organ  remains  undersized  or  rudimentary. 

The  causes  of  atrophy  may  be  pathologic,  from  disease 
or  other  injurious  agency,  as  in  atrophy  of  the  testicle 
after  orchitis;  or  it  may  be  physiologic,  as  the  atrophy 
of  organs  after  their  period  of  functional  activity  is 
passed,  as  the  atrophy  of  the  thymus  at  puberty,  the 
ovaries  and  mammae  at  the  menopause. 

Degeneration. — The  term  "degeneration"  is  applied 
to  a  condition  in  which  a  tissue  is  converted  into 
tissue  of  a  different  character  and  lower  vitality. 

Cloudy  Swelling. — This  form  of  degeneration  occurs 
most  frequently  in  the  kidney  and  liver.  The  normal 
cells  become  swollen,  cloudy,  and  vacuolated.  It  is 
caused  by  fever,  poisons,  bacterial  toxins,  etc. 

Fatty  Degeneration. — Under  the  influence  of  various 
toxic  substances,  as  lead,  mercury,  arsenic,  bacterial  poi- 

139 


140  PATHOLOGY 

sons,  anemia,  cachexia,  etc.,  normal  tissue  cells  are  con- 
verted into  fatty  tissue.  This  occurs  most  frequently 
in  the  heart  muscle,  the  tissues  of  the  kidney,  liver, 
blood-vessels,  and  nervous  system.  Other  degenerations 
are  amyloid,  mucoid,  hyaline. 

Necrosis  is  the  term  used  to  define  the  condition  of 
local  tissue  death. 

The  causes  of  necrosis  are  trauma  or  chemical  injury, 
as  in  crushing  injuries  and  acid  burns;  thermal  injuries, 
as  in  freezing  or  burning;  nutritional  or  circulatory  dis- 
turbances, as  thrombosis,  embolism,  atheroma,  cachexia, 
senility,  and  diabetes. 

Coagulation  Necrosis. — This  is  a  form  of  tissue  death 
in  which  there  occurs  a  coagulation  of  the  dead  tissue 
similar  to  the  coagulation  of  blood.  It  is  more  often 
the  result  of  bacterial  poisons,  though  it  occurs  as  a  re- 
sult of  chemical  irritants  and  thermal  injuries. 

Liquefaction  Necrosis. — In  this  form  pf  tissue  death 
the  dead  tissues  become  liquefied.  In  coagulation  ne- 
crosis the  dead  tissues  become  firmer  and  stiffer,  while 
in  liquefaction  necrosis  they  become  fluid  or  semifluid. 
It  occurs  most  frequently  in  the  brain,  less  often  in  the 
skin  and  heart  muscle. 

Caseation. — This  is  the  term  applied  to  the  form  of 
necrosis  in  which  the  dead  tissue  is  transformed  into  a 
cheese-like  substance.  It  is  exemplified  in  the  cheese- 
like  degeneration  which  takes  place  in  the  tubercle  of 
tuberculosis. 


PLATE  ill 


Senile  dry  gangrene  of  the  lower  extremity  (Hektoen  in  ''  American 
Text-book  of  Pathology  "). 


RETROGRADE  PROCESSES  141 

Gangrene  may  be  defined  as  necrosis  with  putre- 
faction of  the  necrotic  tissue. 

Dry  gangrene  is  the  form  in  which  the  tissues  become 
mummified.  It  occurs  chiefly  in  parts  of  the  body  ex- 
posed to  the  air,  and  is  exemplified  in  senile  gangrene 
of  the  extremities,  which  is  caused  by  failure  of  the 
blood-supply  to  the  extremities,  and  also  in  gangrene 
which  follows  freezing  of  the  extremities. 

Black  Gangrene. — When  the  gangrene  has  been  pre- 
ceded by  congestion,  the  dead  blood  colors  the  necrotic 
tissue  black,  giving  rise  to  the  term  black  gangrene. 

White  Gangrene. — When  the  part  is  anemic  at  the 
time  of  death  and  is  not  afterward  permeated  with 
blood,  it  remains  pale,  and  the  condition  is  called  white 
gangrene. 

Moist  Gangrene. — This  form  of  gangrene  occurs  in 
the  presence  of  liquids,  and,  therefore,  is  found  chiefly  in 
deep-seated  tissues,  as  the  lungs,  bowels,  appendix, 
kidneys,  etc.  The  necrosed  tissue  remains  soft  in  these 
localities  and  often  liquefies. 


CHAPTER  XX 
INFLAMMATION  AND  PROCESSES  OF  REPAIR 

INFLAMMATION 

INFLAMMATION  is  essentially  a  local  tissue  degenera- 
tion combined  with  exudation  from  the  blood-vessels, 
caused  by  some  injurious  agency,  with  which  is  associ- 
ated, earlier  or  later,  tissue  proliferation,  leading  to 
regeneration  or  hypertrophy  (Ziegler). 

The  four  cardinal  symptoms  of  inflammation,  as 
designated  by  Celsus,  are:  Color  (heat),  rubor  (redness), 
tumor  (swelling),  dolor  (pain),  to  which  was  added  later 
functio  Icesa  (altered  function). 

Causes  of  Inflammation. — Traumatic,  as  blows  and 
mechanical  injuries.  Chemical ,  as  stings  of  insects,  ivy- 
poisoning,  acid  injuries,  etc.  Thermal,  as  heat  and  cold. 
Specific,  as  bacteria  erysipelas,  peritonitis,  etc. 

CONSIDERATION  OF  THE  PROCESSES  OF  INFLAMMATION 

Hyperemia. — The  onset  of  inflammation  is  marked  by 
dilation  of  the  blood-vessels  and  a  quickening  of  the 
blood-current,  which  accounts  for  the  heat  and  redness. 
This  is  quickly  followed  by  slowing  of  the  current  and 
exudation. 

142 


PLATE  IV 


Changes  in  the  blood-vessels  and  tissues   due    to  inflammation.       (From 
Russell  Howard's  "Surgical  Nursing,"  by  permission  of  the  author.) 

A.  Normal  capillary  blood-vessel   and   connective  tissue  :   f.t.,  Fibrous   tis- 
sue ;  c.tc,  connective-tissue  cell  ;  w.c.,  white  blood  corpuscle  ;  c.,  capillary  ;  e.t., 
elastic  tissue. 

B.  First  change.      Dilatation    and  congestion  of  blood-vessel  ;    the  white 
cells  arranged  along  the  sides  of  the  vessel  wall  ;   exudation  of  serum. 

C.  Second  change.    Blood-vessel  dilated  and  congested  ;  exudation  of  white 
cells  (phagocytes);   multiplication  of  fixed  connective-tissue  cells  ;  fibrous  and 
elastic  tissue  indistinct. 

D.  Third  change.     Rupture  of  the  congested  vessel  and  escape  of  red  cor- 
puscles ;  multiplication  of  connective-tissue  cells  ;  normal  tissue  very  indistinct. 

E.  Pus.     Breaking  down  of  the  whole  tissue,  due  to  the  presence  of  micro- 
organisms ;   suppuration. 

F.  Chronic  inflammation.     Blood-vessel  small  ;    great  increase  of  fibrous 
tissue. 


INFLAMMATION  AND  PROCESSES  OF  REPAIR      143 

Exudation. — As  the  blood-current  slows  down  the 
white  blood-corpuscles  gather  along  the  vessel  walls, 
through  which  they  presently  begin  to  pass,  prompted, 
no  doubt,  by  a  change  in  the  walls  of  the  vessels  and  an 
attraction  for  the  irritant  that  is  causing  the  inflamma- 
tory reaction.  Along  with  this  migration  of  the  leuko- 
cytes there  occurs  an  exudation  of  inflammatory  lymph 
which  is  modified  blood-serum.  This  infiltration  of  the 
tissues  with  leukocytes  and  lymph  is  the  origin  of  the 
"tumor"  or  swelling. 

DEGENERATIVE  CHANGES 

Any  irritant  sufficient  to  cause  inflammation  causes 
more  or  less  tissue  degeneration  or  necrosis,  so  we  have 
as  a  part  of  inflammation  more  or  less  necrosis. 

Proliferation. — In  all  inflammation  of  any  extent  there 
occurs  a  certain  amount  of  connective-tissue  cell  pro- 
liferation. It  is  probable  that  this  is  an  attempt  on  the 
part  of  nature  to  supply  new  tissue  to  take  the  place  of 
that  injured  or  destroyed  by  the  inflammatory  process. 

Resolution. — The  recovery  from  an  inflammatory 
process  occurs  more  or  less  as  follows:  The  leukocytes 
re-enter  the  blood-vessels  or  pass  into  the  lymph- vessels. 
The  liquid  exudate  is  absorbed  by  the  blood-vessels  or 
lymphatics;  the  necrotic  tissue  is  either  removed  by 
the  phagocytes  or  becomes  liquefied  and  is  absorbed. 
The  regenerated  tissue  remains  and  takes  the  place  of 
the  destroyed  tissue,  forming  what  is  termed  a  scar. 


144  PATHOLOGY 

Cicatrix  or  Scar. — The  replacement  of  tissue  destroyed 
by  inflammation  or  otherwise  by  a  peculiar  form  of 
connective  tissue,  called  scar  tissue,  is  called  cicatriza- 
tion, and  the  result  is  called  a  scar  or  cicatrix. 

Suppuration. — This  is  an  inflammatory  condition  in 
which  necrotic  tissue  and  inflammatory  exudate  are 
liquefied  by  the  action  of  pyogenic  micro-organisms. 

Pus. — The  liquid  resulting  from  the  process  of  sup- 
puration is  called  pus.  It  is  composed  of  white  blood- 
corpuscles,  broken-down  tissue  cells,  serum,  bacteria, 
etc. 

Abscess. — When  a  circumscribed  area  of  suppuration 
occurs  within  the  substance  of  a  tissue  or  an  organ,  the 
lesion  is  termed  an  abscess.  An  abscess  may,  therefore, 
be  defined  as  a  circumscribed  collection  of  pus  sur- 
rounded by  a  restraining  wall  of  proliferative  tissue, 
which  has  been  referred  to  as  "the  pyogenic  membrane," 
from  the  mistaken  idea  that  it  was  concerned  in  the 
production  of  the  contents  of  the  abscess. 

Diffuse  Cellulitis  or  Purulent  Infiltration.— When 
suppuration  within  a  tissue  or  organ  does  not  become 
circumscribed,  but  spreads  through  the  substance  of  the 
tissue  or  organ,  the  condition  is  known  as  diffuse  cellu- 
litis  or  purulent  infiltration.  This  condition  is  usually 
due  to  streptococcus  infection. 

Ulcer. — Suppurative  conditions  upon  the  surface  of 
an  organ  or  tissue  (i.  e.,  upon  the  skin  or  mucous  mem- 
branes) give  rise  to  erosions  termed  ulcers.  An  ulcer 


INFLAMMATION  AND  PROCESSES  OF  REPAIR      145 

corresponds  histologically  to  an  abscess,  the  outer  wall 
of  which  is  missing.  The  base  of  the  ulcer,  being 
composed  of  granulation  tissue,  corresponds  to  the 
pyogenic  membrane  of  an  abscess. 

Sinus. — A  sinus  is  the  tortuous  track  by  which  a  deep- 
seated  abscess  opens  upon  the  surface.  A  sinus  cannot 
heal  until  the  suppurating  surface  or  cavity  which  it 
drains  ceases  to  suppurate. 

WOUND  REPAIR  »  REGENERATION 
Healing  by  First  Intention. — When  the  lips  of  a  clean 
aseptic  wound  are  brought  in  apposition,  proliferative 
connective-tissue  cells  join  the  apposing  walls,  prolifer- 
ative epithelial  cells  close  over  the  surface,  and  the 
wound  is  said  to  have  healed  by  first  intention. 

Healing  by  Second  Intention. — Should  the  walls  of 
the  wound  not  be  brought  into  apposition,  or  be  exposed 
to  irritants,  or  become  infected,  granulations  spring  up 
on  the  apposing  surfaces,  filling  up  the  intervening  space. 
This  granulation  tissue  is  gradually  converted  into 
fibrous  tissue,  the  old  epithelial  cells  at  the  edges  of 
the  wound  proliferate  and  cover  over  the  surface  of 
the  new-formed  fibrous  tissue,  and  the  wound  is  said 
to  have  healed  by  granulation  or  second  intention. 

PROGRESSIVE  PROCESSES 

Hypertrophy. — The  term  "hypertrophy"  is  used  to 
designate  that  pathologic  condition  in  which  a  tissue  or 
10 


146  PATHOLOGY 

organ  increases  in  size  through  the  increase  in  size  or 
multiplication  of  its  elemental  cells.  Thus  the  structure 
of  the  hypertrophied  tissue  does  not  differ  materially 
from  normal  tissue. 

Simple  hypertrophy  is  due  to  an  increase  in  size  of  the 
individual  cells  of  the  organ,  and  is  exemplified  in  the 
hypertrophy  of  the  pregnant  uterus  and  in  compensatory 
hypertrophy  of  the  heart. 

Hyperplasia  or  numeric  hypertrophy  consists  of  an 
increase  in  the  number,  but  not  in  the  size,  of  the  indi- 
vidual cells  composing  an  organ  or  tissue. 


CHAPTER  XXI 

TUMORS 

A  TUMOR  may  be  described  as  an  atypic  non-inflam- 
matory proliferation  of  a  tissue  of  embryonal  or  post- 
natal origin  (Hektoen). 

Causes  of  Tumor  Formation. — Though  many  theories 
have  been  advanced  in  explanation  of  the  phenomena  of 
tumor  growth,  a  definite  etiology  is  as  yet  unknown. 
Virchow  held  that  tumors  were  due  to  external  irrita- 
tion, but  while  there  occur  frequent  instances  of  tumors 
following  irritation,  such  as  smokers'  cancer  of  the  lip 
and  carcinoma  of  the  breast  following  irritation  and  in- 
flammation of  the  nipple,  there  are  too  many  instances 
of  tumors  occurring  without  previous  irritation  for  the 
acceptance  of  this  theory.  Cohnheim  held  that  all 
tumors  were  due  to  misplaced  islands  of  embryonic 
tissue  (embryonic  rests),  which  under  favorable  condi- 
tions set  up  growth  and  development  independent  of 
the  tissues  in  which  they  were  planted.  It  is  true  that 
certain  tumors  most  certainly  do  originate  in  this  way, 
but,  like  the  irritation  theory,  it  cannot  be  held  applic- 
able to  all  tumor  growths. 

147 


148  PATHOLOGY 

The  infectious  theory  of  the  origin  of  tumors  is  also 
advocated,  but  the  fact  remains  that  the  absolute  cause 
of  tumors  is  as  yet  unknown. 

Structure. — The  elemental  cells  of  tumors  do  not  differ 
greatly  from  normal  cells  of  a  like  kind,  but  the  relations 
of  the  cells  to  each  other  and  of  the  tissues  composing 
the  tumor  are  invariably  atypic. 

Classification  of  Tumors. — Tumors  are  sometimes 
classified  according  to  their  embryonic  origin,  those 
developing  from  the  middle  embryonic  layer  or  meso- 
blast  being  termed  connective-tissue  tumors,  while 
those  developing  from  the  hypoblastic  or  epiblastic 
layers,  being  composed  of  epithelium  as  well  as  con- 
nective tissue,  are  called  epithelial  tumors. 

Tumors  are  also  classified,  according  to  their  danger 
to  life,  as  benign  and  malignant  tumors. 

Benign  tumors  are  those  which  do  not  spread  or  recur 
after  removal,  do  not  affect  the  general  health,  and  are 
only  dangerous  secondarily  through  pressure  on  vital 
organs  or  hemorrhage. 

Malignant  tumors  affect  the  general  health,  usually 
causing  death  eventually.  They  tend  to  recur  after 
removal  and  spread  to  other  parts  by  metastasis. 

CONNECTIVE-TISSUE  TUMORS 

Fibroma. — A  fibroma  is  a  benign  tumor  composed  of 
fibrous  tissue.  Springing  from  pre-existing  connective 
tissue,  fibromata  are  found  in  numerous  localities,  the 


TUMORS  149 

more  important  examples  being  fibromata  of  the  uterus, 
ovaries,  and  mammary  gland.  Less  frequently  they 
spring  from  the  submucous  connective  tissue  of  the  nose 
and  the  subcutaneous  connective  tissue  of  the  skin. 

Myxoma. — Myxomata  are  benign  tumors  composed 
largely  of  a  form  of  mucous  tissue  having  a  connective- 
tissue  framework  and  an  intercellular  substance  of  a 
gelatinous  nature.  Myxomata  occur  in  submucous  and 
subcutaneous  connective  tissue  and  in  the  mammary 
gland,  brain,  spinal  cord,  and  nerves. 

Lipoma. — Lipomata  are  benign  tumors  composed  of 
adipose  tissue.  The  growths  occur  in  the  subcutaneous 
tissue  of  the  back,  buttocks,  thighs,  and  abdomen, 
less  frequently  in  the  kidneys,  mammary  gland,  and 
brain. 

Chondroma. — Chondromata  are  benign  tumors  com- 
posed almost  exclusively  of  cartilage.  A  small  amount 
of  connective  tissue  acts  as  a  framework  for  the  blood- 
vessels of  the  growth.  Chondromata  usually  occur  in 
bone  periosteum  or  cartilage,  but  are  occasionally 
found  in  the  testicle,  ovary,  and  parotid  gland,  where 
their  presence  must  be  accounted  for  on  the  theory  of 
a  misplaced  matrix  of  cartilaginous  tissue. 

Osteoma. — Osteomata  are  benign  tumors  composed  of 
bone.  They  are  found  usually  in  connection  with  bony 
or  cartilaginous  tissue,  though,  like  chondromata,  they 
also  occur  in  the  testicle,  ovary,  and  parotid  gland. 
The  most  common  example  of  osteoma  is  the  exostosis 


150  PATHOLOGY 

occurring  at  the  metatarsophalangeal  joint  in  connection 
with  the  affection  termed  bunion. 

Angioma. — Angiomata  are  benign  tumors  composed 
of  blood-  or  lymph-vessels.  Those  composed  of  blood- 
vessels are  called  hemangiomata,  while  those  com- 
posed of  lymph-vessels  are  termed  lymphangiomata. 
Strictly  speaking,  these  are  usually  but  enlargements 
and  dilations  of  existing  vessels.  In  some  instances, 
however,  actual  proliferation  of  vessels  occurs,  espe- 
cially in  hemangiomata. 

Vascular  nevi,  or  Port  wine  birth-marks,  are  angio- 
mata  of  congenital  origin. 

Myoma. — Myomata  are  benign  tumors  composed  al- 
most exclusively  of  muscular  fibers. 

Leiomyomata  are  composed  of  smooth  muscular  fibers, 
and  occur  most  frequently  in  the  uterus. 

Rhabdomyomata  are  composed  of  striated  muscular 
fibers,  and  occur  in  the  kidney,  uterus,  vagina,  muscles, 
etc. 

Glioma. — Gliomata  are  benign  tumors  composed  of 
neuroglia  or  the  cells  of  the  stroma  of  the  central  nervous 
system.  These  growths  occur  in  the  brain  and  spinal 
cord.  While  they  are  benign  tumors,  they  are  often 
dangerous  to  life  because  of  their  location. 

Neuroma. — Neuromata  are  benign  tumors  composed 
of  nerve-fibers.  True  neuromata  are  rare.  False  neuro- 
mata (fibrous  growths  springing  from  the  endoneurium 
or  perineurium  of  nerves)  are,  in  reality,  a  form  of 


TUMORS  151 

fibroma.  The  most  important  of  these  forms  of  growth 
are  the  amputation  neuromata,  occurring  at  the  site 
of  amputations.  They  also  occur  along  the  course  of 
nerves,  independent  of  amputation  or  injury. 

Lymphadenoma. — This  is  a  malignant  form  of  growth 
composed  of  lymphadenoid  tissue.  It  occurs  in  the 
lymphatic  glands  and  other  adenoid  tissues.  The  exact 
relation  of  this  form  of  tumor  growth  to  Hodgkin's 
disease  is  not  well  understood.  It  is  probably  one 
manifestation  of  this  disease. 

Lymphosarcoma. — Lymphosarcomata  are  simply  the 
forms  of  lymphadenomata  which  partake  of  the  char- 
acter of  sarcoma.  It  is  doubtful  if  there  exists  any 
material  distinction  between  lymphadenoma  and 
lymphosarcoma.  They  are  both  probably  forms  of 
sarcoma. 

Sarcoma. — Sarcomata  are  malignant  growths  com- 
posed of  connective  tissue  closely  resembling  the  embry- 
onal type,  having  an  abundance  of  cells  and  little  inter- 
cellular substance.  Sarcomata  always  arise  from  meso- 
blastic  tissue,  as  bone,  cartilage,  or  connective  tissue. 
They  occur  in  the  bones,  periosteum,  brain,  liver,  lungs, 
and  intestines.  They  most  frequently  affect  children 
or  young  adults.  They  form  metastases  through  the 
circulation,  recur  after  operation,  and  are  always 
fatal. 

Various  forms  are  designated  according  to  their 
histologic  structure,  such  as  spindle-celled  sarcoma, 


152  PATHOLOGY 

giant-celled    sarcoma,    small    and    large    round-celled 
sarcoma. 

Lymphosarcoma.  Melanosarcoma. 

Alveolar  sarcoma.  Chloroma. 

Tubular  sarcoma.  Myxosarcoma. 

Angiosarcoma.  Psammoma. 

Sarcomatous  cylindroma.  Osteosarcoma. 

Adenoma.— Adenomata  are  benign  tumors  which 
spring  from  glands  and  present  a  more  or  less  typic 
glandular  structure.  Adenomata  occur  in  the  skin, 
mucous  membranes,  mammary  glands,  liver,  kidneys, 
and  ovaries,  wherever  glandular  tissue  exists.  While 
they  are  essentially  benign  in  their  nature,  those  of 
certain  localities,  particularly  of  the  uterus  and 
stomach,  are  prone  to  carcinomatous  degeneration. 

Carcinoma  (Cancer). — Carcinomata  are  malignant 
epithelial  tumors.  They  always  arise  from  epithelial 
structures,  as  the  skin,  mucous  membrane,  glands,  etc., 
and,  spreading  rapidly  by  infiltration  and  metastasis, 
are  usually  rapidly  fatal.  They  occur  most  frequently 
in  those  past  middle  age,  though  no  age  is  exempt  from 
their  devastation.  Many  of  the  lower  animals  are  sus- 
ceptible, including  rats  and  mice,  and  most  of  the  experi- 
mental work  on  cancer  has  been  done  on  rats  and  mice. 
It  has  been  determined  that  in  rare  instances  carcino- 
mata  spontaneously  disappear,  after  which  the  organism 


TUMORS  153 

is  immune  to  this  growth.  This  occurs  in  mice,  where 
tumors  are  transferred  from  one  mouse  to  another,  and 
it  has  been  established  that  recovery  also  occurs,  though 
rarely,  in  human  beings. 

Ascitic  fluid  from  an  individual  who  had  recovered 
from  cancer  has  been  found  to  retard  the  growth  and 
cause  the  disappearance  of  cancer  in  another  individual 
into  whom  it  was  injected.  Thus,  while  the  cause  of 
cancer  remains  a  mystery,  the  conquest  of  the  age-old 
scourge  seems  about  to  be  realized. 

Cancer  occurs  in  all  parts  of  the  body  where  epithelial 
tissue  exists.  Among  the  more  frequent  seats  of  the 
growth  may  be  named  the  skin,  stomach,  intestines, 
esophagus,  tongue,  rectum,  mammary  gland,  ovaries, 
liver,  kidney,  prostate,  and  testicle. 

Histologic  Characteristics  of  Cancer. — In  sarcoma  the 
epithelial  cells  are  distributed  fairly  uniformly  through 
the  stroma,  each  cell  being  surrounded  by  connective- 
tissue  fibrillae,  the  connective  tissue  preponderating.  In 
carcinomata  the  epithelial  cells  preponderate  and  are 
gathered  in  groups  or  cell-nests,  which  are  surrounded  by 
a  stroma  of  connective  tissue.  This  alveolar  structure  is 
always  characteristic  of  carcinoma,  no  stroma  penetrat- 
ing between  the  individual  cells,  as  in  sarcoma.  These 
epithelial  plugs  infiltrate  the  surrounding  tissue,  invade 
the  lymph-channels,  and  are  soon  found  in  the  regional 
lymph-glands.  From  the  glands  the  general  circula- 
tion is  invaded  and  metastatic  tumors  occur  in  distant 


154  PATHOLOGY 

organs  or  tissues.  Rarely  the  tumor  cells  pass  directly 
into  the  circulation.  This  is  more  characteristic,  how- 
ever, of  sarcoma.  After  attaining  a  certain  size  or  stage 
of  development,  degeneration  of  cancer  occurs.  This 
may  take  the  form  of  mucoid,  colloid,  hyalin,  or  amyloid 
degeneration  or  necrosis,  which  is  probably  hastened 
by  infection.  The  degenerative  changes,  however, 
never  equal  the  growth  of  the  tumor. 

Varieties  of  Cancer.— Flat-celled  Carcinoma.— This 
develops  from  all  squamous  or  stratified  epithelium. 

Melanocarcinoma. — This  is  a  flat-celled  carcinoma 
containing  pigment.  It  develops  from  squamous  or 
stratified  epithelium. 

Columnar-celled  Carcinoma. — This  arises  from  tissue 
containing  cylindric  epithelium. 

Colloid  Carcinoma. — This  is  a  columnar-celled  car- 
cinoma in  which  the  cancer  cells  have  undergone  colloid 
degeneration,  usually  occurring  in  the  digestive  tract. 

Adenocarcinoma. — This  tumor  develops  from  glandu- 
lar tissue  and  simulates  glandular  tissue  in  its  structure. 

This  is  divided  into  simple,  in  which  the  cells  and 
stroma  are  about  equal;  medullary,  in  which  the  cells 
predominate;  scirrhus,  in  which  the  stroma  is  in  excess. 
The  scirrhous  variety  is  found  in  the  breast,  stomach, 
ovaries,  and  testicle. 

Giant-celled  Carcinoma. — A  rare  form  in  which  the 
cells  attain  a  large  size  from  various  causes. 


TUMORS  155 

TERATOMA  AND  TERATOID  TUMORS 

These  are  tumors  composed  of  all  three  layers  of  the 
embryo — hypoblast,  mesoblast,  and  epiblast. 

These  tumors,  may,  in  general,  be  looked  upon  as 
arising  from  misplaced  fetal  remnants. 

Dermoid  Cyst. — This  is  a  benign  tumor,  though  some- 
times prone  to  carcinomatous  degeneration.  It  is  com- 
posed of  a  connective-tissue  membrane  lined  with  skin. 
Its  contents  are  the  various  appendages  of  the  skin, 
such  as  hairs,  sebaceous  glands,  and  occasionally  teeth. 
They  grow  very  slowly  and  may  remain  latent,  varying 
in  size  from  that  of  a  pea  to  enormous  masses.  They 
are  found  most  frequently  in  the  ovaries,  less  frequently 
in  the  testicles,  peritoneum,  membranes  of  the  brain,  in 
the  neck,  floor  of  the  mouth,  and  about  the  eye.- 

Bigeminal  Teratoma. — In  this  form  of  tumor  we  have 
the  implantation  of  an  ovum  or  fetus  upon  or  within 
the  tissues  of  another  fetus.  The  misplaced  organism 
may  remain  dormant,  while  the  one  upon  which  it  is 
implanted  develops  slightly  or  to  considerable  extent, 
giving  rise  to  various  monsters.  Where  the  extra 
fetus  is  enclosed  within  another,  it  is  termed  endogenous 
teratoma;  where  two  are  fused,  one  developing  only  in 
part,  it  is  called  ectogenous  teratoma. 


CHAPTER  XXII 

PARASITES  AND  DISEASE   (VEGETABLE  PARASITES) 

Bacteria. — We  have  learned  in  our  study  of  bacteri- 
ology that  bacteria  are  an  important  cause  of  disease 
processes.  We  will  now,  in  pathology,  consider  the 
diseases  of  which  they  are  the  cause,  and  the  altera- 
tions in  structure  and  function  of  the  organs  and  tissues 
affected  by  their  growth  and  multiplication  within  the 
body. 

Local  Effects  Upon  the  Tissues  of  Bacterial  Growth. 
—The  local  effects  of  bacterial  activity  may  be  either 
mechanical  or  histologic. 

Mechanically,  the  clumps  of  bacteria  may  obliterate 
small  vessels,  leading  to  thrombosis,  necrosis,  or  infarct. 
By  the  production  of  membranes,  as  in  diphtheria,  they 
may  occlude  the  air-passages,  causing  suffocation. 

The  histologic  effects  of  bacterial  growth  are  both 
proliferative  and  degenerative.  Among  the  prolifer- 
ative  processes  may  be  mentioned  the  formation  of 
tumor-like  growths,  as  gumma  in  syphilis,  tubercle  in 
tuberculosis,  the  nodular  formation  in  leprosy,  and 
the  proliferative  changes  in  the  vessel  walls  occurring 
in  late  syphilis.  Of  the  degenerative  changes,  necrosis 
is  the  most  important,  as  exemplified  in  the  various  ul- 

156 


PARASITES  AND  DISEASE   (VEGETABLE  PARASITES)      157 

cerations,  in  phagedenic  ulcer,  and  the  local  tissue  death 
of  dental  caries.  Degenerative  changes  also  occur 
secondary  to  many  of  the  proliferative  processes,  as  in 
the  necrosis  of  tubercles. 

The  effects  of  the  products  of  bacteria  are  sometimes 
local,  but  they  are  more  often  of  a  general  nature.  The 
toxins  may  cause  local  suppuration  or  they  may  enter 
the  circulation  and  become  localized  in  some  special 
tissue,  as  the  localization  of  tetanus  toxin  in  the  cells 
of  the  central  nervous  system,  to  which  it  is  highly 
destructive,  though  harmless  to  other  tissues  of  the 
body.  Other  toxins  have  a  selective  action  also,  as 
the  preference  of  the  diphtheria  toxin  for  involuntary 
muscle  cells. 

DISEASES  DUE  TO  BACTERIA 

SUPPURATIVE    DISEASES    (FURUNCULOSIS,    ABSCESS,   OSTEO- 
MYELITIS,   OTITIS  MEDIA,   MASTOIDITIS,  ETC.) 

Definition. — Diseases  characterized  by  the  formation 
of  pus. 

Etiology. — The  usual  cause  of  these  disorders  is  the 
introduction  into  the  tissues  of  the  Staphylococcus 
albus,  aureus,  and  citreus,  streptococcus,  under  certain 
conditions  the  pneumococcus,  and  the  gonococcus.  The 
typhoid  bacillus  and  the  colon  bacillus  give  rise  to  sup- 
purative  diseases,  and  they  are  sometimes  present  as 
mixed  infections,  with  the  ordinary  pus  microbes. 

A  lowered  resistance,  debility,  anemia,  and  lowered 
opsonic  index  are  contributory  causes.  That  these 


158  PATHOLOGY 

germs  may  cause  such  diseases  has  been  abundantly 
proved  by  injections  of  cultures  of  the  causative  germ  in 
both  human  beings  and  animals. 

GONORRHEA 

Definition. — A  contagious  catarrhal  inflammation  of 
the  genital  mucous  membrane  due  to  the  gonococcus. 

Etiology. — The  specific  cause  of  this  disease  is  infec- 
tion with  the  gonococcus.  This  has  been  proved  by 
direct  inoculation  with  the  germ.  Infection  practically 
always  occurs  through  sexual  intercourse,  although  in- 
stances of  innocent  infection  do  occur  from  use  of  towels, 
clothing,  chambers,  etc. 

Morbid  Anatomy. — The  organism  causes  a  suppurative 
inflammation  of  the  mucous  surfaces  with  which  it 
comes  in  contact.  The  germs  tend  to  penetrate  deeply 
into  the  surrounding  tissue,  sometimes  giving  rise  to 
peri-urethral  abscess.  It  sometimes  enters  the  blood 
and,  locating  in  the  heart,  induces  endocarditis  in  the 
joints,  causing  arthritis,  etc. 

Morbid  Physiology. — The  disturbances  of  function 
occurring  in  this  disease  are  due  largely  to  the  germs 
themselves  rather  than  to  their  toxins,  which  are  not 
capable  of  producing  the  characteristic  symptoms  of  the 
disease. 

LOBAR  PNEUMONIA 

Definition. — An  acute  infectious  disease  characterized 
by  inflammation  of  the  lungs,  toxemia,  and  fever. 


PARASITES  AND  DISEASE   (VEGETABLE  PARASITES)     159 

Etiology. — The  exciting  cause  of  this  disease  is  the 
Diplococcus  pneumoniae,  its  presence  having  been  de- 
monstrated in  a  large  proportion  of  the  cases  investigated. 
That  predisposing  causes  and  the  virulence  of  the  germ 
are  factors  in  the  causation  of  the  disease  is  shown  by 
the  fact  that  the  germ  is  found  in  the  air-passages  of 
healthy  individuals.  Of  predisposing  causes,  age  plays 
an  important  part,  the  majority  of  cases  occurring  in 
infancy  and  old  age.  Lowered  vitality  from  exposure, 
overwork,  poor  food,  alcoholism,  previous  debilitating 
diseases,  as  influenza,  typhoid,  etc.,  injuries  to  chest, 
and  ether-anesthesia  are  also  predisposing  factors. 

Morbid  Anatomy. — In  this  disease,  instead  of  isolated 
areas,  the  entire  lobe  of  the  lung  is  affected.  The  in- 
flammatory process  is  divided  into  four  stages,  which  are 
designated  as  engorgement,  red  hepatization,  gray  he- 
patization,  and  resolution. 

Engorgement. — In  this  stage  of  the  disease  the  lung 
tissue  is  deep  red  in  color,  the  capillaries  are  dilated  and 
tortuous.  The  alveoli  contain  red  blood-corpuscles, 
round  cells,  and  detached  epithelial  cells,  but  are  not  as 
yet  completely  occluded. 

Red  Hepatization. — In  this  stage  the  surface  shows 
the  indentation  of  the  ribs.  Its  consistency  is  firm  and 
friable.  The  alveoli  are  completely  filled  with  fibrin, 
red  and  white  blood-cells,  epithelium,  bacteria,  and 
granular  debris.  The  bronchial  mucous  membrane  is 
reddened  and  engorged,  the  smaller  bronchi  often  con- 


160  PATHOLOGY 

tain  fibrous  plugs.  The  cut  surface  of  the  lung  presents 
a  granular,  reddish-brown  appearance  resembling  liver 
tissue,  hence  the  name  hepatization. 

Gray  Hepatization. — In  this  stage  the  tissue  has 
changed  from  reddish-brown  to  grayish-white  in  color. 
The  air-cells  are  filled  with  leukocytes,  the  fibrin  and 
red  blood-cells  having  largely  disappeared. 

Resolution. — In  this  stage  liquefaction  of  the  alveolar 
contents  takes  place  partially  through  autolytic  diges- 
tion and  partially  by  mucoid  and  fatty  degeneration. 
The  liquefied  mass  is  expectorated,  absorbed,  and  ex- 
creted by  the  kidneys,  air  again  enters  the  alveoli,  and 
the  parts  gradually  approach  the  normal. 

Morbid  Physiology. — Interference  with  respiratory 
function  is  proportionate  to  the  amount  of  the  lung  in- 
volved and  the  pain  and  fever  present.  The  absorption 
of  toxins  causes  profound  systemic  disturbances,  evi- 
denced by  prostration,  high  temperature,  weak  heart 
action  and  low  blood-pressure,  and  leukocytosis.  The 
diplococcus  may  enter  the  blood  and  give  rise  to  compli- 
cations in  distant  organs,  as  endocarditis,  pericarditis, 
and  meningitis. 

DIPHTHERIA 

Definition. — An  acute  infectious  and  contagious  dis- 
ease due  to  the  Klebs-LorHer  bacillus,  characterized  by 
a  fibrous  exudate  at  the  site  of  infection  and  constitu- 
tional symptoms  due  to  toxins  produced  at  the  site  of 
the  lesion. 


PLATE  W  *   ;,   : 


Croupous  pneumonia,  stage  of  gray  hepatization  (Bollinger). 


PARASITES  AND  DISEASE   (VEGETABLE  PARASITES)     161 

Etiology. — The  exciting  cause  is  the  diphtheria  bacillus. 
The  frequent  presence  of  the  germ  in  healthy  throats  in- 
dicates the  necessity  of  predisposing  causes,  among  which 
are  lowered  resistance  and  personal  susceptibility,  en- 
larged tonsils,  pharyngitis,  laryngitis,  etc.  Infection  may 
occur  from  food,  especially  milk,  from  books,  toys,  from 
persons  in  contact  with  the  disease,  and  from  healthy 
carriers  of  the  bacillus:  Age  is  important.  Sucklings 
are  very  slightly  susceptible.  From  the  second  to  the 
fifth  year  the  susceptibility  increases,  then  gradually 
decreases. 

Morbid  Anatomy. — This  is  essentially  a  local  disease 
of  the  larynx,  pharynx,  or  nose,  with  systemic  and  vis- 
ceral lesions  due  to  the  absorption  of  the  toxins.  Locally 
there  is  produced  upon  the  mucous  membrane  at  the 
site  of  infection  a  false  membrane.  There  is  necrosis 
of  the  epithelium,  followed  by  an  inflammatory  exudate 
rich  in  fibrin,  which,  in  conjunction  with  the  dead  epi- 
thelial cells,  form  the  false  membrane.  The  germs  grow 
and  develop  upon  the  necrotic  tissue  and  not  upon  the 
living  tissue.  Removal  of  the  false  membrane  leaves 
a  raw  and  bleeding  surface  beneath,  the  depth  to  which 
the  tissues  are  affected  depending  upon  the  amount  of 
necrosis.  This  membrane  may  block  the  nasal  passages, 
extend  to  the  conjunctiva,  and  through  the  Eustachian 
tubes  to  the  middle  ear. 

It  may  block  the  larynx  or  extend  into  the  trachea  or 

bronchi.     The  internal  lesions  are  due  to  the  toxin,  as 
11 


162  PATHOLOGY 

the  germs  are  not  usually  found  in  the  circulation.  They 
consist  of  fatty  degeneration  of  the  heart  muscle  and 
acute  interstitial  myositis.  The  kidneys  are  also  affected, 
the  lesions  varying  from  simple  degeneration  to  intense 
nephritis.  The  liver  and  spleen  show  degenerative 
changes,  with  foci  of  necrosis.  Degeneration  of  the 
peripheral  nerves  and  neuritis  also  occurs. 

Morbid  Physiology. — While  deglutition  and  interfer- 
ence with  respiration  may  occur  from  the  presence  of 
the  membrane  and  inflammatory  reaction,  the  lesion  is 
purely  a  local  one,  and  the  systemic  disturbances  (chill, 
fever,  prostration,  and  visceral  lesions)  are  caused  by  the 
toxin,  which  is  very  soluble  and  highly  toxic.  Intro- 
duction of  the  toxin  into  animals  reproduces  practi- 
cally all  the  general  manifestations  of  the  disease.  Va- 
rious degrees  of  susceptibility  to  the  toxin  and  also  to 
the  growth  of  the  germ  exist,  so  that  frequently  an  ex- 
aggerated local  lesion  is  accompanied  by  slight  consti- 
tutional disturbances  and  vice  versa.  An  attack  con- 
fers temporary  immunity. 

CEREBROSPINAL  FEVER 

Definition. — An  acute  infectious  disease  caused  by 
the  meningococcus  and  characterized  by  inflammation 
of  the  cerebrospinal  meninges  and  a  clinical  course  of 
great  irregularity. 

Etiology. — Epidemics  of  this  disease  are  localized, 
and  occur  with  greater  frequency  in  the  country  than 


PARASITES  AND  DISEASE  (VEGETABLE  PARASITES)     163 

in  cities.  Infection  must  depend  upon  a  particular 
susceptibility,  as  it  is  rare  to  have  more  than  one  case 
in  a  home,  and  carriers  are  frequently  found  who, 
though  perfectly  healthy  themselves,  carry  the  germs  in 
their  throats  or  noses.  It  seems  not  to  be  contagious. 
Heat,  overexertion,  squalor,  and  want  appear  to  be  pre- 
disposing causes.  Sporadic  cases  occur  at  all  times. 
Flexner  has  demonstrated  by  animal  inoculations  that 
the  meningococcus  is  the  cause  of  the  disease,  and  has 
perfected  a  curative  serum. 

Morbid  Anatomy. — The  brain  and  cord  show  intense 
congestion,  accompanied  in  cases  that  have  lasted  a  week 
by  a  fibropurulent  exudate  most  marked  at  the  base  of 
the  brain.  Sometimes  the  entire  cortex  may  be  covered 
with  exudate.  The  cerebrospinal  fluid  is  turbid  and 
contains  the  meningococcus.  In  chronic  cases  there  may 
be  general  thickening  of  the  meninges.  Petechia  of  the 
skin  may  occur,  giving  to  the  disease  the  name  spotted 
fever.  Other  organs  of  the  body  are  but  slightly  affected, 
though  pericarditis,  pleurisy,  and  parotitis  may  occur. 

Morbid  Physiology. — Because  of  the  location  of  the 
infectious  process  in  the  brain  and  spinal  cord  the  per- 
version of  function  is  widespread.  There  are  chills, 
fever,  vomiting,  headache,  convulsions,  and  paralysis. 
Mental  disturbances,  delirium,  mania,  stupor,  or  coma 
may  be  present.  Increased  leukocytosis  is  a  constant 
and  persistent  condition.  Cases  which  recover  are  usu- 
ally mentally  defective  or  suffer  from  various  paralyses, 


1 64  PATHOLOGY 

blindness,   deafness,   etc.     Recovery  after  the  use  of 
Flexner's  serum  is  not  accompanied  by  these  defects. 

TYPHOID  FEVER 

Definition. — An  infectious  disease  caused  by  the 
Bacillus  typhosus  and  characterized  by  hyperplasia  and 
ulceration  of  the  intestinal  lymph-follicles,  and  swelling 
of  the  mesenteric  glands  and  spleen. 

Etiology. — The  specific  cause  is  the  typhoid  germ, 
which  gains  entrance  to  the  body  through  the  alimentary 
canal,  locating  in  the  intestinal  glands.  Predisposing 
causes  are  lowered  vitality  from  any  cause.  The  great- 
est susceptibility  exists  between  the  ages  of  fifteen  and 
twenty-five.  Infants  are  rarely  attacked.  The  most 
frequent  sources  of  infection  are  milk  and  water,  though 
any  food-product  which  is  eaten  raw  may  convey  the 
infection. 

Flies  are  probably  the  greatest  disseminators  of  in- 
fection. One  attack  usually  confers  immunity  for  life, 
but  a  second  and  even  a  third  attack  may  occur.  The 
germs  may  persist  in  the  bile-passages  and  intestines 
of  persons  fully  recovered  from  the  disease.  Such 
carriers  become  a  serious  menace  to  all  with  whom  they 
may  come  in  contact. 

Morbid  Anatomy. — A  catarrhal  condition  exists 
throughout  the  large  and  small  intestines.  There  is 
hyperplasia  of  Peyer's  patches,  which  become  infil- 
trated, hardened,  and  elevated  above  the  mucous  mem- 
brane. The  solitary  glands  may  project  into  the  in- 


PLATE  VI 


Ileum;  typhoid  fever  (early  stage):  Peyer's  patches  and  solitary  folli- 
cles greatly  swollen;  superficial  ulceration  (Nicholls  in  "  American  Text- 
book of  Pathology"). 


PARASITES  AND  DISEASE   (VEGETABLE  PARASITES)     165 

testines.  The  swollen  follicles  may  undergo  resolution 
or  the  process  may  go  on  to  necrosis  and  sloughing. 
This  is  due  in  part  to  a  choking  and  obliteration  of  the 
blood-vessels  by  the  infiltration,  and  in  part  to  the  direct 
action  of  the  bacilli  upon  the  cells.  Following  and  de- 
pendent upon  the  sloughing  there  occurs  ulceration. 
The  necrotic  tissue  gradually  separates,  beginning  at 
the  periphery  of  the  gland,  finally  becoming  detached  and 
leaving  ulcers  of  varying  sizes  and  depths.  Upon  the 
separation  of  the  slough,  cicatrization  begins.  The 
ulcers  diminish  in  size,  the  floor  becoming  covered  with 
a  layer  of  delicate  granulations.  The  mucosa  gradually 
extends  in  from  the  edge,  and  a  new  growth  of  epithelium 
is  formed.  The  mesenteric  glands  are  infiltrated,  en- 
larged, and  softened,  but  seldom  suppurate.  The 
spleen  is  enlarged  and  softened,  and  parenchyma tous 
degeneration  may  occur  in  all  the  tissues  of  the  body- 
kidneys,  liver,  heart,  blood-vessels,  nervous  system, 
and  bone-marrow. 

Morbid  Physiology. — In  addition  to  interference  with 
the  function  of  the  intestines  by  the  local  manifesta- 
tions of  the  disease,  the  toxin  produces  widespread  dis- 
turbances in  other  organs.  Changes  occur  in  the 
blood,  with  an  increase  of  the  agglutinins,  giving  rise 
to  the  Widal  reaction,  with,  finally,  the  establishment  of 
immunity.  The  fever,  apathy,  delirium,  and  the  various 
parenchymatous  degenerations  are  doubtless  due  to  the 
toxin. 


i66  PATHOLOGY 

ASIATIC  CHOLERA 

Definition. — An  acute  infectious  disease  caused  by 
the  Cholera  spirillum,  characterized  by  violent  purging 
and  rapid  collapse. 

Etiology. — The  specific  cause  of  this  disease  is  the 
Cholera  spirillum.  Infection  occurs  in  the  intestine,  as 
in  typhoid  fever,  the  source  of  infection  being  food  or 
drink  contaminated  with  the  excretions  of  cholera 
patients.  That  predisposing  causes  exist  is  evidenced 
by  the  frequent  presence  of  virulent  cholera  germs  in 
the  stools  of  healthy  individuals.  What  the  predis- 
posing factors  may  be  we  are  as  yet  unable  to  say, 
though  depressing  emotions,  fear,  and  debility  may 
have  something  to  do  with  an  increased  susceptibility. 

Morbid  Anatomy. — The  peritoneum  is  sticky  and  the 
intestines  congested  and  shrunken.  Peyer's  glands  and 
Brunner's  glands  are  enlarged.  The  mucosa  is  swollen 
and  congested.  The  germs  are  found  in  the  intestinal 
contents  and  mucous  membrane.  There  is  more  or  less 
fatty  degeneration  of  the  liver  and  cloudy  swelling  and 
extensive  coagulation  necrosis  of  the  kidneys. 

Morbid  Physiology. — The  profound  disturbances  of 
function  which  occur  in  this  disease  are  due  to  the  toxin 
of  the  germ.  There  are  vomiting  and  diarrhea.  Secre- 
tion of  the  urine  and  saliva  are  arrested  and  the  blood 
becomes  thick,  due  to  the  rapid  extraction  of  water 
from  the  body  in  the  watery  stools. 


PARASITES  AND  DISEASE   (VEGETABLE  PARASITES)     167 
TUBERCULOSIS 

Definition. — An  infective  disease  caused  by  the  Bacil- 
lus tuberculosis.  So  termed  because  of  the  formation  in 
its  lesions  of  small  nodular  bodies  called  tubercles. 

Etiology. — There  is  perhaps  no  disease  to  which  the 
animal  kingdom  is  more  universally  susceptible.  It  is 
transmitted  by  means  of  the  secretions  of  susceptible 
animals.  Cattle,  hogs,  and  man  are  the  most  suscep- 
tible; rabbits  and  guinea-pigs  less  so;  as  are  also  cats 
and  dogs,  which  are,  however,  sometimes  infected  by 
tuberculous  masters.  Monkeys  appear  to  be  immune 
in  the  wild  state,  but  exceedingly  susceptible  in  captiv- 
ity, bearing  out  the  fact  that  tuberculosis  is  a  house- 
bred  disease. 

Heredity  was  formerly  considered  an  important  pre- 
disposing cause,  it  being  thought  than  an  increased  sus- 
ceptibility was  transmitted  from  parent  to  offspring. 
It  is  probable  that  this  is  greatly  overestimated,  and 
that,  indeed,  in  case  of  parents  who  have  recovered  from 
tuberculous  infection  a  certain  degree  of  immunity  or 
increased  resistance  to  infection  is  transmitted  to  the 
offspring.  The  most  important  predisposing  causes 
are  overwork,  underfeeding,  and  poorly  ventilated  liv- 
ing quarters.  There  is  perhaps  no  disease  in  which  the 
susceptibility  is  so  increased  by  bad  living,  debilitating 
diseases,  as  measles,  whooping-cough,  pneumonia,  grip, 
etc. 

The  modes  of  infection  are  inhalation,  ingestion  (in 


l68  PATHOLOGY 

tuberculous  milk),  direct  inoculation  through  wounds  of 
the  skin,  or  through  the  genital  tract.  Direct  transmis- 
sion to  the  fetus  in  utero  occurs,  but  is  rare.  The  trans- 
mission from  one  member  of  a  family  to  another  is  fre- 
quent. 

Morbid  Anatomy. — No  organ  of  the  body  is  free  from 
the  manifestations  of  this  disease.  The  order  of  fre- 
quency in  which  the  organs  are  affected  in  this  disease 
are  as  follows:  lungs,  lymph-glands,  bones  and  joints, 
intestines,  peritoneum,  kidneys,  brain,  spleen,  liver,  and 
generative  organs.  Wherever  the  infection  is  located 
it  is  characterized  by  the  formation  of  tubercles.  The 
evolution  of  a  tubercle  is  thus  described  by  Baumgarten: 

(1)  There  is  a  rapid  multiplication  of  the  tubercle 
bacilli,  which  is  accompanied  by  their  dissemination  in 
the  surrounding  tissues,  partly  by  growth  and  partly 
by  the  lymph-current. 

(2)  Multiplication  of  the  fixed  cells,  especially  those 
of  the  connective  tissue  and  the  endothelium  of  the 
capillaries,  and  the  gradual  production  from  them  of 
rounded   cuboid   or   polygonal   bodies   with   vesicular 
nuclei,  the  epithelioid  cells,  inside  some  of  which  bacilli 
are  seen. 

(3)  From  the  vessels  of  the  infected  focus  leukocytes 
(chiefly  polynuclear)  migrate  in  numbers  and  accumulate 
about  the  focus  of  infection.     They  do  not  long  survive, 
however,   and  many  undergo  destruction.     Later,   as 
the  little  tubercles  grow,  the  leukocytes  found  are  of 


»  '  •» 

PLATE  Vflf  *'"''•"' 


Tuberculosis  of  the  lung:  the  upper  lobe  shows  advanced  cheesy  con- 
solidation with  cavity  formation,  bronchiectasis,  and  fibroid  changes; 
the  lower  lobe  retains  its  spongy  texture,  but  is  occupied  by  numerous 
miliary  tubercles  (McFarland). 


PARASITES  AND  DISEASE  (VEGETABLE  PARASITES)     169 

the  mononuclear  variety,  which  do  not  undergo  the 
rapid  degeneration  of  the  polynuclears. 

(4)  A  reticulum  of  fibers  is  formed  by  the  fibrillation 
and  rarefaction  of  the  connective-tissue  matrix.    This 
is  most  apparent,  as  a  rule,  at  the  margin  of  the  growth. 

(5)  In  some  tubercles  giant  cells  are  formed  by  in- 
crease in  the  protoplasm  and  in  the  nuclei  of  the  indi- 
vidual cells,  or  possibly  by  the  fusion  of  several  cells. 

Once  formed  the  tubercle  may  undergo — 

Caseation. — At  the  center  of  the  tubercle  the  cells 
under  the  action  of  the  bacilli  and  their  toxins  undergo 
coagulation  necrosis  and  are  converted  into  a  structure- 
less mass.  The  process  extends  until  the  entire  tubercle 
is  converted  into  a  cheesy,  homogeneous  mass,  in  which 
the  bacilli  are  still  active,  after  which  it  may  undergo 
softening,  encapsulation,  or  calcification. 

Instead  of  caseation,  which  must  be  looked  upon  as 
degenerative  and  dangerous,  the  tubercle  may  undergo — 

Sclerosis. — With  the  destruction  of  the  cells  at  the 
center  of  the  tubercle  there  may  occur  fibroid  transform- 
ation at  the  periphery,  the  tubercle  being  converted  into 
a  firm  resistant  mass.  It  is  in  this  manner  that  healing 
occurs. 

By  the  fusion  of  softened  caseous  tubercles,  cavities 
are  formed  which  are  sometimes  termed  cold  abscesses, 
because  of  the  absence  of  true  pus  in  their  contents. 

Morbid  Physiology. — In  addition  to  the  disturbances 
of  function  which  the  tuberculous  infection  causes  at 


170  PATHOLOGY 

the  site  of  infection,  toxins  are  formed  which  cause  con- 
stitutional symptoms  of  varying  intensity.  There  is 
anemia,  wasting,  afternoon  rise  of  temperature,  and 
more  or  less  weakness.  The  nature  of  the  toxic  products 
are  not  well  understood.  The  well-known  reaction  to 
tuberculin  in  the  presence  of  tuberculous  infection  and 
absence  of  reaction  where  infection  does  not  exist,  would 
indicate  a  process  differing  somewhat  from  the  ordinary 
toxin  production  of  toxic  infections. 

LEPROSY 

Definition. — A  chronic  infectious  disease  caused  by 
the  Bacillus  leprae.  Characterized  by  the  formation 
of  tuberculous  nodules  in  the  skin  and  mucous  mem- 
branes, or  by  trophic  changes  in  the  nerves,  or  by  both 
together. 

Etiology. — Of  the  mode  of  infection  little  is  known. 
Some  particular  susceptibility  must  be  necessary  for 
infection  to  occur,  because,  with  a  single  exception, 
attempts  at  direct  inoculation  have  failed,  while  physi- 
cians and  nurses  who  care  for  lepers  rarely  ever  con- 
tract the  disease.  Heredity  is  supposed  to  play  a  part, 
yet  no  case  is  on  record  of  leprosy  in  the  newborn. 

Morbid  Anatomy. — In  the  tuberculous  form,  nodules 
composed  of  granulomatous  tissue  occur  on  the  skin 
of  the  face,  hands,  and  forearms,  less  frequently  upon 
other  parts  of  the  body.  Between  the  nodules  are  some- 
times seen  areas  of  ulceration  and  cicatrization.  On 


PARASITES  AND  DISEASE   (VEGETABLE  PARASITES)     171 

the  face  this  process  produces  a  peculiar  appearance 
termed  facies  leontina.  The  mucous  membranes  may 
be  similarly  affected  and  blindness  may  occur  from  in- 
volvement of  the  conjunctiva  and  cornea,  or  loss  of 
voice  and  suffocation  from  involvement  of  the  larynx. 
Ulcer ations  may  lead  to  the  loss  of  toes  or  fingers.  In 
the  anesthetic  form  there  is  almost  entire  absence  of  the 
deformities  seen  in  the  tuberculous  variety  of  the  disease. 
There  may,  however,  be  in  this  form  maculae  and  pem- 
phigus-like bullae  of  the  skin  which  may  ulcerate,  thus 
leading  to  deformity  and  contractions  or  loss  of  fingers 
and  toes. 

Morbid  Physiology. — The  alterations  of  function  in  this 
disease  are  entirely  local,  as  there  seems  to  be  no  tox- 
emia present.  Secondary  lesions  may  occur  in  internal 
organs — liver,  spleen,  testes,  lungs,  etc. — which  are 
similar  to  the  skin  lesions.  The  anesthetic  variety  lays 
the  parts  liable  to  various  injuries  from  trauma,  freezing, 
burns,  etc.,  because  of  the  loss  of  sensation. 

PLAGUE 

Definition. — An  acute  infectious  disease  caused  by  the 
Bacillus  pestis,  characterized  by  inflammation  of  the 
lymphatic  glands,  pneumonia,  and  hemorrhages. 

Etiology. — Filth,  squalor,  and  poverty  undoubtedly 
contribute  to  the  existence  and  spread  of  the  disease. 
Infection,  especially  in  the  pneumonic  type  of  the  disease, 
may  occur  by  direct  dissemination  of  the  germ  by  in- 


172  PATHOLOGY 

fected  individuals.  Inoculation  of  cutaneous  wounds 
may  also  occur,  though  the  bacillus  is  short  lived  out- 
side the  body  and  rapidly  disappears  from  water,  soil, 
and  air.  The  most  important  mode  of  infection  is  by 
inoculation  by  the  bite  of  the  rat  flea.  Rats,  ground 
squirrels,  mice,  guinea-pigs,  and  monkeys  are  very  sus- 
ceptible to  the  disease,  and  practically  every  outbreak 
of  the  disease  among  human  beings  is  coincident  with  an 
epidemic  among  rats.  If  the  rats  are  free  of  fleas  close 
contact  of  healthy  with  infected  animals  does  not  in- 
fect healthy  animals,  while  the  mere  transference  of 
fleas  from  infected  animals  to  healthy  ones  without  any 
association  of  healthy  with  infected  animals  is  sufficient 
to  cause  an  outbreak  of  the  disease  among  the  healthy. 
It  would  seem  that  the  pneumonic  type  is  acquired 
by  inhalation  of  infected  material,  while  the  bubonic 
form  is  transferred  from  rats  to  man  by  the  flea.  While 
rat  fleas  do  not  normally  attack  man,  yet  upon  the 
death  of  their  normal  host  they  leave  the  dead  body  in 
search  of  warmth  and  nourishment,  and  will  then  take 
up  their  abode  temporarily  upon  the  bodies  of  human 
beings. 

Morbid  Anatomy. — There  is  swelling  and  inflammation 
of  the  lymphatic  glands,  which  tend  to  suppurate.  The 
inflammation  sometimes  extends  to  the  adjacent  tissues 
with  extravasations  of  blood.  The  inguinal  glands  are 
most  constantly  affected,  though  those  of  the  axilla, 
neck,  and  mediastinum  may  also  be  affected. 


PARASITES  AND  DISEASE  (VEGETABLE  PARASITES)     173 

The  spleen  and  intestinal  follicles  are  enlarged. 
Parenchymatous  degeneration  of  the  heart,  liver,  and 
kidneys  may  be  found.  Ecchymosis  and  petechiae  and 
carbuncles  of  the  skin  are  frequent.  In  the  pneumonic 
form  inflammation  of  the  lungs  resembling  pneumococcus 
infection  takes  place. 

Morbid  Physiology. — While  there  is  considerable 
question  regarding  the  character  of  the  toxin  formed  by 
this  microbe,  the  existence  of  such  toxin  is  evidenced  by 
the  profound  systemic  disturbances  (chills,  fever,  ap- 
proaching 108°  F.  at  times,  delirium,  stupor,  and  coma). 
The  heart's  action  is  feeble  and  rapid,  and  collapse 
may  take  place. 

TETANUS 

Definition. — An  acute  infectious  disease  caused  by  the 
Bacillus  tetani,  characterized  by  more  or  less  persistent 
tonic  spasms  of  the  voluntary  muscles,  particularly 
those  of  the  jaw. 

Etiology. — The  bacillus  is  found  in  great  numbers  in 
cultivated  soil,  street  dust,  horse  manure,  and  stable 
detritus.  Infection  would,  therefore,  be  expected  to 
be  a  frequent  occurrence.  That  infection  is  a  relatively 
rare  occurrence  is  due  to  the  specific  limitations  to  the 
growth  and  development  of  the  germ. 

Being  a  pure  anaerobe,  the  germ  must  be  protected 
from  oxygen  for  its  growth  and  development,  and  in- 
fection can,  therefore,  occur  only  in  punctured  or  deep- 
seated  wounds.  There  seems  also  to  be  a  considerable 


174  PATHOLOGY 

resistance  to  the  development  of  the  germs,  so  that  pure 
cultures  freed  from  toxin  and  injected  into  animals  do 
not  develop.  If,  however,  they  are  accompanied  by 
saprophytic  germs,  chemicals,  or  other  material  which 
may  cause  a  lowered  vitality  of  the  surrounding  tissues, 
development  and  toxin  formation  takes  place.  So  we 
find  wounds  into  which  foreign  material  has  been  carried, 
as  wads  in  blank-cartridge  wounds,  pieces  of  clothing, 
dust,  etc.,  are  particularly  prone  to  become  the  seat  of 
tetanus  infection.  The  uterus  (following  delivery)  and 
the  umbilicus  of  the  newborn  furnish  fertile  fields  for 
infection. 

Morbid  Anatomy. — There  are  very  few  anatomic 
changes  present  in  this  disease.  Some  congestion  of 
the  membranes  of  the  brain  and  cord  are  seen,  and  re- 
cently some  structural  alterations  of  the  ganglionic  cells 
of  the  cord  have  been  described. 

Morbid  Physiology. — The  bacilli  remain  localized  and 
cause  little  or  no  disturbance.  All  the  symptoms  are 
caused  by  the  toxin,  which  reaches  the  brain  and  cord 
by  way  of  the  axis-cylinders  of  the  nerve-trunks  and  not 
by  way  of  the  blood-  and  lymph-channels.  The  toxin 
has  a  peculiar  affinity  for  the  cells  of  the  central  nervous 
system,  and  is  seemingly  harmless  to  other  tissues. 
Its  effect  upon  the  nervous  system  is  similar  to  strychnin, 
causing  violent  spasms  of  the  voluntary  muscles.  It 
is  eliminated  by  the  urine,  which  is  highly  toxic.  An 
antitoxin  is  elaborated  in  the  blood  of  infected  indi- 


PARASITES  AND  DISEASE   (VEGETABLE  PARASITES)      175 

viduals,  but  seems  incapable  of  separating  the  toxin 
from  the  nerve- tissue  once  it  has  been  united  with  it. 
Antitoxin  treatment,  therefore,  to  be  of  value  must  be 
administered  before  the  nervous  symptoms  denote  the 
union  of  toxin  with  the  cells  of  the  nerve-tissue. 

GLANDERS 

Definition. — An  infectious  disease  caused  by  the 
Bacillus  mallei,  occurring  usually  in  animals,  occasionally 
in  man,  and  characterized  by  enlargement  of  the  lym- 
phatic glands,  especially  of  the  parotid  and  submaxillary 
chains,  with  catarrhal  inflammation  of  the  nasal  and 
respiratory  mucous  membranes. 

Etiology. — The  specific  cause  is  infection  with  the 
Bacillus  mallei,  predisposing  causes  being  occupations 
which  bring  man  in  contact  with  horses.  Veterinarians, 
coachmen,  teamsters,  stablemen,  and  stockmen  are 
practically  the  only  ones  who  have  the  disease. 

Morbid  Anatomy. — The  histologic  changes  resemble 
those  of  pyemia.  Peculiar  bloody  abscesses  and  ulcers 
occur  over  the  surface  of  the  body.  In  the  skin,  mucous 
membranes,  lungs,  liver,  brain,  and  spleen  are  found 
nodules  of  varying  size,  from  a  pin-point  to  that  of 
a  walnut.  The  nodules  are  found  to  be  made  up  of 
necrotic  or  caseous  material  in  the  center  surrounded  by 
epithelioid  cells,  leukocytes,  and  small  round  cells. 
Lymph-glands  near  the  nodules  are  infiltrated  and  en- 
larged. 


176  PATHOLOGY 

Morbid  Physiology. — There  are  symptoms  referable  to 
a  toxin,  as  fever,  headache,  and  prostration.  Painful, 
red  and  swollen  joints,  profuse  and  fetid  expectoration. 

ANTHRAX 

Definition. — An  acute  infectious  disease  caused  by  the 
anthrax  bacillus,  occurring  usually  in  animals,  but  oc- 
casionally in  man.  Characterized  by  hard  edema  or 
ulcers  at  the  point  of  inoculation  and  symptoms  of 
collapse. 

Etiology. — The  exciting  cause  is  the  bacillus  of  anthrax 
which,  in  cattle  and  sheep,  gains  entrance  through  the 
alimentary  canal.  In  man  the  infection  occurs  from 
handling  cattle  or  sheep  or  their  products,  as  wool, 
hides,  hair,  etc.,  and  takes  place  by  direct  inoculation 
through  the  skin,  by  inhalation  through  the  respira- 
tory tract,  and  by  ingestion  through  the  elementary 
tract. 

Morbid  Anatomy. — The  most  common  form  of  anthrax 
in  man  is  due  to  skin  infection,  and  takes  the  form  of  a 
localized  abscess  or  pustule  termed  malignant  pustule. 
This  may  heal  or  progress  to  general  septicemia.  The 
pulmonary  form,  or  wool-sorters'  disease,  gives  rise  to 
inflammation  of  the  lungs  resembling  pneumonia. 
Septicemia  may  follow.  Where  septicemia  occurs,  the 
blood  is  found  teeming  with  the  germs,  which  may  even 
clog  the  capillaries. 

Morbid  Physiology. — The  influence  of  this  infection 


«  c     *  .  c 


PLATE  VIII 


Actinomycosis  of  the  cheek  (Tllich). 


PARASITES  AND  DISEASE  (VEGETABLE  PARASITES)     177 

upon  the  physiologic  processes  is  not  well  understood. 
No  toxin  has  been  demonstrated,  though  an  attack  con- 
fers immunity,  and  the  symptoms  of  the  intestinal 
form — diarrhea,  vomiting,  fever,  and  rapid  pulse — 
resemble  a  toxemia.  In  view  of  the  fact  that  immunity 
may  be  produced  by  vaccination,  both  with  attenuated 
and  dead  cultures,  it  would  seem  that  the  immunity  was 
a  result  of  phagocytosis.  The  opsonic  index  is  high  in 
immune  animals  and  low  in  susceptible  ones,  which 
would  also  support  the  phagocytic  theory  of  the  im- 
munity. 

ACTINOMYCOSIS 

Definition. — A  chronic  infectious  disease  of  cattle, 
occurring  occasionally  in  man,  caused  by  Actinomyces 
bovis  and  characterized  by  the  formation  of  lumpy 
tumors. 

Etiology. — The  disease  is  due  to  a  peculiar  vegetable 
organism  termed  the  ray  fungus.  It  occurs  chiefly  in 
cattle,  but  occasionally  in  man,  the  horse,  pig,  sheep, 
dog,  cat,  and  elephant.  The  mode  of  infection  is  still 
in  question,  instances  occurring  in  individuals  having 
no  association  with  cattle.  Nor  has  there  been  any 
observation  of  instances  of  direct  contagion  among 
cattle.  Because  of  the  frequency  of  infection  in  the 
jaw  and  about  the  throat  it  is  supposed  to  occur  through 
carious  teeth. 

Morbid  Anatomy. — This  organism  produces  a  granu- 
lation tumor  consisting  of  proliferating  connective-tissue 
12 


178  PATHOLOGY 

cells  and  some  epithelioid  or  giant  cells.  Suppuration 
of  the  growth  soon  takes  place  and  the  ray  fungus  is 
found  in  the  pus. 

Morbid  Physiology. — The  functional  disturbances  are 
due  almost  entirely  to  the  local  process  or  the  septic 
complications  which  may  arise.  There  are  no  toxins 
formed.  Generalization  of  the  infection  may  occur  in 
man,  and  emboli  may  cause  death. 

INFLUENZA 

Definition. — An  epidemic  disease  caused  by  the 
Bacillus  influenzae,  characterized  by  fever,  depression, 
muscular  pains,  and  acute  catarrhal  inflammation  of 
the  nose,  larynx,  and  bronchi. 

Etiology. — The  disease  is  extremely  contagious,  though 
the  modes  of  infection  are  not  well  understood.  Doubt- 
less the  direct  transference  of  the  infection  from  one 
individual  to  another  is  the  usual  manner  in  which  it 
takes  place. 

Morbid  Anatomy. — There  are  no  specific  lesions  in 
influenza.  The  mucous  membranes  of  the  air-passages 
are  congested  and  swollen.  The  bacilli  have  been  found 
in  the  brain  in  cerebral  influenza,  and  in  the  intestines 
between  the  epithelial  cells  and  in  the  basement-mem- 
brane. ,  %'  ; 

Morbid  Physiology.— But  little  is  known  of  the  cause 
of  the  constitutional  disturbances  in  this  disease. 
They  are  characteristic  of  a  toxemia,  but  a  toxin  has 


PARASITES  AND  DISEASE   (VEGETABLE  PARASITES)     179 

not  as  yet  been  isolated.     Immunity  is  not  established 
by  an  attack;  in  fact,  increased  susceptibility  seems  to 

follow. 

SYPHILIS 

Definition. — A  specific  infectious  disease  of  slow  evo- 
lution, caused  by  the  Treponema  pallidum. 

Etiology. — The  cause  of  this  disease  has  at  last  been 
definitely  proved  to  be  the  Treponema  pallidum  by  the 
inoculation  of  apes,  which  seem  to  be  the  only  animal 
besides  man  which  is  susceptible  to  the  infection. 
The  infection  occurs  through  minute  abrasions  of  the 
skin  and  mucous  membranes,  and  is  usually  transmitted 
by  sexual  intercourse.  Innocent  infection  frequently 
occurs  in  nurses  and  physicians  from  examining  and 
handling  syphilitic  patients,  and  in  others  through  kiss- 
ing, the  use  of  drinking  vessels,  etc. 

Hereditary  transmission  is  frequent,  this  being  one 
of  the  few  diseases  in  which  the  direct  transmission  of 
the  disease  from  parent  to  offspring  may  occur.  The 
inheritance  may  come  from  either  parent.  A  remarkable 
fact  concerning  inherited  syphilis  is  that  referred  to  as 
Colics'  law,  which  is  stated  as  follows :  If  a  syphilitic  child 
be  born  of  a  healthy  mother,  the  child  cannot  infect  such 
mother,  though  if  it  suckle  a  healthy  wet-nurse  the  nurse 
will  become  infected.  The  mother  doubtless  receives 
immunity  by  way  of  the  placenta  without  being  herself 
infected. 

Morbid  Anatomy.— The  pathologic  manifestations  of 


i8o  PATHOLOGY 

this  disease  are  divided  into  three  stages:  the  primary, 
secondary,  and  tertiary. 

Primary  Lesion. — In  the  primary  stage  there  occurs 
at  the  site  of  infection  an  initial  lesion  termed  chancre. 
This  appears  as  a  small  papule  or  vesicle  which  is  red- 
dened and  inflamed.  This  soon  becomes  eroded  and 
surrounded  by  a  zone  of  infiltration  of  peculiar  hard- 
ness, termed  induration.  This  consists,  histologically, 
of  a  diffuse  infiltration  of  round  cells,  large  epithelioid 
cells,  and  giant  cells.  Changes  occur  in  the  small 
arteries  and  veins,  leading  to  an  acute  obliterative  en- 
darteritis  which  causes  the  peculiar  stony  induration. 
The  neighboring  lymphatic  glands  undergo  hyperplasia 
and  become  indurated. 

Secondary  Lesions. — After  a  variable  length  of  time, 
from  three  weeks  to  several  months,  the  secondary 
manifestations  of  the  disease  appear.  These  include 
swelling  and  induration  of  the  superficial  lymphatic 
glands.  Various  eruptions — macular,  papular,  and 
scaly — make  their  appearance  upon  the  skin.  On  the 
mucous  membrane  occur  condylomata  or  mucous 
patches,  somewhat  elevated  patches  with  superficial 
ulceration  or  erosion. 

Tertiary  Lesions. — The  most  distinctive  lesions  of  this 
stage  are  circumscribed  tumors,  known  as  gummata, 
various  skin  lesions,  ulcers,  etc.,  and  a  peculiar  type  of 
arteritis. 

Gummata  are  nodular  masses  varying  in  size  from 


PARASITES  AND  DISEASE  (VEGETABLE  PARASITES)     181 

small  tubercles  to  masses  the  size  of  an  orange  or 
larger,  occurring  in  bones,  periosteum,  muscle,  skin, 
brain,  lungs,  liver,  kidneys,  heart,  testes,  and  adrenals. 
These  masses  are  composed  largely  of  round  cells  from 
the  blood-vessels  and  various  proliferated  connective- 
tissue  cells  of  spindle  shape  or  irregular  forms.  Epithe- 
lioid  cells  are  few  in  number.  There  are  various  changes 
in  the  vessel  walls  and  new  formation  of  blood-vessels. 
Necrosis  may  occur  at  the  center  of  gummata,  and  fatty 
or  myxomatous  degeneration  is  common.  Atheroma 
of  the  arteries  may  lead  to  softening  of  the  brain. 

Morbid  Physiology. — It  is  probable  that  the  physio- 
logic disturbances  in  this  disease  are  due  to  the  germ 
itself,  which  is  recovered  from  all  the  lesions  of  the  dis- 
ease rather  than  from  a  specific  toxin.  Antibodies  are 
found  in  the  blood  of  infected  individuals,  and  this  fact 
is  taken  advantage  of  in  the  Wassermann  or  deviation 
of  complement  test.  All  efforts  to  establish  either 
active  or  passive  immunity  have  thus  far  failed, 
though  Ehrlich  has  succeeded  in  ridding  the  system  of 
the  disease  by  injections  of  an  arsenic  preparation 
termed  salvarsan  or  "606. " 

RELAPSING  FEVER 

Definition. — A  specific  infectious  disease,  caused  by 
the  Spirochaeta  obermeieri,  characterized  by  recurring 
paroxysms  of  fever  and  separated  afebrile  periods. 

Etiology. — Overcrowding,  deficient  food,  squalor,  and 


182  PATHOLOGY 

filth  seem  to  be  conditions  favorable  to  infection  with 
this  germ.  Just  how  the  infection  occurs  is  not  known, 
but  it  is  suspected  that  bed-bugs  or  fleas  may  be  instru- 
mental in  its  transference. 

Morbid  Anatomy. — There  are  no  characteristic  ana- 
tomic alterations  in  this  disease.  Ecchymoses  of  the 
skin  occur,  and  there  have  been  found  enlargement  of 
the  spleen,  cloudy  swelling  of  the  heart,  liver,  and 
kidneys,  and  infarcts  of  the  kidney  and  spleen,  also 
changes  in  the  bone-marrow. 

Morbid  Physiology. — No  toxins  have  been  demon- 
strated in  this  disease,  but  antibodies  for  the  germs  are 
developed  during  each  paroxysm  of  fever  that  rapidly 
destroy  the  germs,  which  are  then  taken  up  by  the 
phagocytes.  Some,  however,  appear  to  withstand  the 
effects  of  the  antibodies  and  develop  and  multiply  after 
an  interval,  either  because  of  the  partial  disappearance 
of  the  antibodies  or  to  an  immunity  of  the  surviving 
germs.  When  growth  and  development  of  the  germs 
begin  again,  another  paroxysm  of  fever  occurs,  which  is 
ended  as  before  by  the  development  of  antibodies  and 
phagocytosis.  The  blood  becomes  finally  so  charged 
with  antibodies  that  further  growth  of  the  germs  is  im- 
possible, and  recovery  occurs,  with  immunity  to  further 
infection.  The  blood  of  such  immune  animals  confers 
immunity  on  animals  injected  with  it,  and  is  also  cura- 
tive when  infection  has  already  occurred. 


PARASITES  AND  DISEASE  (VEGETABLE  PARASITES)     183 
MALTA  FEVER 

Definition. — An  endemic  infectious  disease  due  to  the 
Micrococcus  melitensis,  characterized  by  irregular  fever, 
sweats,  arthritis,  and  enlarged  spleen. 

Etiology. — While  it  is  believed  that  this  infection  may 
be  transmitted  by  mosquito  bites,  the  usual  mode  of 
infection  is  the  drinking  of  the  milk  of  goats  which  are 
infected.  The  milk  abounds  with  the  germs,  and  mon- 
keys have  been  infected  with  milk  containing  the  organ- 
ism. 

Morbid  Anatomy. — There  are  no  characteristic  ana- 
tomic changes  in  this  disease. 


CHAPTER  XXIII 

DISEASES   WHOSE   MICROBIC   CAUSE   HAS   NOT    BEEN 
ISOLATED 

THERE  yet  remain  a  number  of  diseases  for  considera- 
tion which  are  most  certainly  of  microbic  origin.  The 
causative  germs,  however,  have  not  been  isolated  and 
subjected  to  Koch's  rules.  The  list  of  such  diseases  is 
growing  shorter  every  year. 

HYDROPHOBIA 

Definition. — An  infectious  disease  communicated  by 
the  bite  of  an  animal  and  characterized  by  severe  nervous 
disturbances  and  spasms,  especially  of  the  muscles  of 
respiration  and  deglutition. 

Etiology. — This  is  probably  due  to  a  specific  micro- 
organism which  has  not  yet  been  isolated.  All  mammals 
are  susceptible  to  the  disease.  The  mode  of  infection 
is  probably  always  through  the  bite  of  an  infected 
animal,  usually  the  dog,  though  cats,  wolves,  horses, 
and  cattle  may  convey  the  disease. 

Morbid  Anatomy. — There  is  congestion  of  the  cord  and 
brain,  as  in  tetanus,  and  some  exudation  in  the  perivas- 
cular  tissue.  Congestion  of  other  organs  may  occur,  as 
of  the  gastro-intestinal  tract,  respiratory  system,  and 
kidneys.  The  only  characteristic  feature  is  the  pres- 
ence in  the  large  nerve-cells  of  the  central  nervous  sys- 

184 


DISEASES  WHOSE  CAUSE  HAS  NOT  BEEN  ISOLATED    185 

tern  of  certain  peculiar  bodies  termed  Negri  bodies,  after 
Negri,  the  investigator  who  first  observed  them.  The 
presence  of  these  bodies  is  considered  pathognomonic 
of  the  disease.  Whether  these  bodies  are  micro-organ- 
isms or  products  of  the  nerve-cells  has  not  yet  been 
determined. 

Morbid  Physiology. — The  alterations  of  function  in  this 
disease  resemble  very  closely  those  of  tetanus,  The 
spasms  of  the  muscles  of  deglutition  are  characteristic. 
They  are  excited  by  attempts  at  swallowing  or  even  the 
thoughts  of  swallowing,  being  provoked  by  the  sight 
of  water.  It  is  from  this  peculiarity  that  the  desease 
derives  its  name.  The  virus  is  found  in  the  spinal  cord 
and  brain  and  is  always  present  in  the  saliva.  It 
makes  its  way  from  the  point  of  infection  to  the  brain 
and  cord  by  way  of  the  nerve-trunks,  as  in  tetanus. 

YELLOW  FEVER 

Definition. — A  fever  of  tropical  and  subtropical  coun- 
tries, characterized  by  jaundice,  albuminuria,  and  a 
tendency  to  hemorrhages  of  the  stomach. 

Etiology. — The  micro-organism  which  causes  this  dis- 
ease has  not  been  isolated,  but  is  known  to  inhabit  the 
blood  of  infected  patients,  as  the  disease  has  been  pro- 
duced by  injecting  the  blood  of  those  infected  into 
healthy  individuals.  The  infection  is  transmitted  from 
individual  to  individual  by  the  bite  of  certain  species 
of  mosquito.  This  has  been  proved  to  be  the  only 


186  PATHOLOGY 

method  of  transmission.  Members  of  the  Yellow  Fever 
Commission  of  the  United  States  Army  slept  for  weeks 
on  the  bedding  of  yellow  fever  patients,  slept  with  the 
patients,  nursed  them,  and  subjected  themselves  to 
every  possible  chance,  but  did  not  take  the  disease  while 
mosquitos  were  excluded.  Mosquitos  were  allowed  to 
bite  patients  with  the  disease  and  afterward  healthy 
individuals,  and  the  disease  followed,  Dr.  Lazear  dying 
from  an  attack.  Colonel  Gorgas  by  exterminating 
mosquitos  stamped  out  yellow  fever  in  Havana. 

Morbid  Anatomy. — The  skin  is  jaundiced  and  hemor- 
rhages occur  from  the  skin  and  mucous  membranes, 
especially  the  mucous  membrane  of  the  stomach,  where 
it  gives  rise  to  the  distinctive  black  vomit  of  the  disease. 
The  lymphatic  glands  are  enlarged  and  there  is  fatty 
degeneration  and  areas  of  necrosis  in  the  liver.  The 
kidneys  show  diffuse  nephritis. 

Morbid  Physiology. — The  fever,  profound  prostration, 
and  the  serious  injury  to  the  liver  and  other  internal 
organs  would  indicate  the  presence  of  a  toxin  in  this 
disease,  but  none  has  been  isolated.  Immunity  is 
established  by  an  attack.  This,  however,  may  be  a 
germicidal  rather  than  a  toxic  immunity. 

MEASLES 

Definition. — An  acute  contagious  disease,  character- 
ized by  catarrhal  inflammation  of  the  upper  air-passages 
and  a  specific  eruption  of  the  skin. 


DISEASES  WHOSE  CAUSE  HAS  NOT  BEEN  ISOLATED    187 

Etiology. — The  disease  is  transmitted  by  contact,  by 
a  third  person,  by  toys,  books,  clothing,  etc.  The  cause 
is  unknown,  as  is  also  the  nature  of  the  contagion. 

Morbid  Anatomy. — There  are  no  characteristic  ana- 
tomic changes.  The  lymphatic  glands  are  enlarged. 
The  eruptive  areas  of  the  skin  show  some  leukocytic 
infiltration. 

Morbid  Physiology. — There  are  no  specific  alterations 
of  function.  Fever  and  catarrhal  disturbances  of  the 
mucous  membranes  are  the  prominent  disturbances. 

SCARLET  FEVER 

Definition. — An  acute  infectious  disease  character- 
ized by  a  scarlet  eruption,  sore  throat,  and  high  fever. 

Etiology. — The  exciting  cause  is  unknown.  Age  is  a 
predisposing  cause.  It  occurs  most  frequently  from  the 
second  to  the  tenth  year;  90  per  cent,  of  cases  occur 
before  the  tenth  year.  There  is  a  great  variation 
of  personal  susceptibility.  Some  individuals  are  ap- 
parently immune.  The  infecting  agent  is  very  resist- 
ant, and  infection  is  often  conveyed  by  clothing,  books, 
toys,  carpets,  etc.,  months  after  the  occurrence  of  the 
disease. 

Morbid  Anatomy. — There  are  no  specific  pathologic 
changes.  The  changes  in  the  throat  are  those  of  any 
simple  inflammation.  The  internal  alterations  are  those 
due  to  fever  and  to  pus  organisms,  which  seem  to  always 
complicate  the  disease.  The  spleen,  liver,  and  Other 


l88  PATHOLOGY 

organs  sometimes  show  necrotic  foci.  The  most  con- 
stant and  typic  complicating  lesion  is  inflammation  of 
the  kidneys,  scarlatinal  nephritis.  Streptococci  are 
constantly  present  in  great  numbers,  and  by  some 
are  considered  to  be  the  cause  of  the  disease.  Certain 
it  is  that  they  are  the  cause  of  many  of  the  complica- 
tions, as  otitis,  mastoiditis,  etc. 

Morbid  Physiology. — The  fever,  prostration,  and  gen- 
eral disturbances  are  simply  characteristic  of  inflamma- 
tion. An  attack  confers  immunity,  but  how  it  does  so 

is  not  known. 

PAROTITIS  (MUMPS) 

Definition. — An  acute  infectious  and  contagious  dis- 
ease, characterized  by  swelling  of  the  parotid  glands  and 
a  liability  to  orchitis. 

Etiology. — The  specific  cause  is  unknown.  The  dis- 
ease occurs  most  frequently  in  childhood  and  early  adult 
life. 

Morbid  Anatomy. — There  is  inflammation  of  one  or 
both  parotid  glands,  with  catarrhal  condition  of  the 
ducts.  Inflammation  of  one  or  both  testicles  may  occur 
and  is  sometimes  followed  by  atrophy.  The  mammary 
glands  and  ovaries  are  less  frequently  involved. 

Morbid  Physiology. — No  specific  alterations  occur. 

PERTUSSIS  (WHOOPING-COUGH) 

Definition. — An  acute  specific  affection,  occurring 
usually  in  children  and  characterized  by  a  peculiar 
convulsive  cough,  ending  with  an  inspiratory  whoop. 


DISEASES  WHOSE  CAUSE  HAS  NOT  BEEN  ISOLATED    189 

Etiology. — The  specific  cause  has  not  been  isolated. 
It  is  extremely  contagious  and  is  usually  transferred 
directly  from  one  individual  to  another.  One  attack 
usually  confers  immunity. 

Morbid  Anatomy. — The  disease  has  no  special  ana- 
tomic changes,  but  enlargement  of  the  tracheal  and 
bronchial  tubes  is  commonly  present. 

Morbid  Physiology. — There  are  no  specific  disturb- 
ances. There  is  increased  leukocytosis,  and  sugar  and 
albumin  may  appear  in  the  urine. 

TYPHUS  FEVER 

Definition. — A  contagious  fever,  characterized  by  high 
temperature,  great  prostration,  and  a  petechial  eruption. 

Etiology. — The  specific  germ  is  as  yet  unknown,  but 
the  contagion  is  probably  conveyed  by  the  breath  and 
secretions  of  the  skin.  Recent  investigations  indicate 
the  presence  of  an  insect  carrier.  Filth,  squalor,  over- 
crowding, poor  ventilation,  and  bad  food  are  doubtless 
predisposing  causes. 

Morbid  Anatomy. — Changes  characteristic  of  high 
fever  occur,  as  enlargement  of  the  spleen  and  swelling 
of  the  kidneys.  The  liver  is  enlarged  and  softened,  and 
granular  degeneration  of  the  muscles,  especially  of  the 
heart,  is  frequent.  A  petechial  rash  of  the  skin  is 
present. 

Morbid  Physiology. — The  disturbances  of  function  are 
those  of  fever. 


CHAPTER  XXIV 

DISEASES  DUE  TO  ANIMAL  PARASITES 
DISEASES  DUE  TO  PROTOZOA 

AMEBIC  DYSENTERY 

Definition. — An  acute  or  chronic  colitis  due  to  the 
Amoeba  dysenteriae. 

Etiology. — The  disease  usually  occurs  in  tropical 
climates.  Nothing  is  known  of  the  life-history  of  the 
ameba  outside  the  body,  but  infection  probably  occurs 
through  drinking-water  or  raw  foods.  Amebae  are 
found  in  the  stools  of  healthy  individuals,  but  whether 
there  exists  an  immunity  in  some  persons  or  whether 
there  are  pathogenic  and  non-pathogenic  varieties  of 
the  parasite  is  not  at  present  known. 

Morbid  Anatomy. — Ulcerations  of  the  walls  of  the 
large  bowel  are  always  present  in  this  disease.  Abscess 
of  the  liver  frequently  accompanies  the  intestinal  pro- 
cess. The  disease  progresses  by  a  gradual  infiltration 
of  the  connective- tissue  layers  of  the  intestines.  The 
infiltration  is  composed  of  proliferative  connective- 
tissue  cells.  Amebae  are  found  in  the  ulcers  and  the 
surrounding  lymphatic  spaces. 

190 


DISEASES  DUE  TO  ANIMAL  PARASITES  191 

Morbid  Physiology. — There  are  general  functional 
disturbances.  The  condition  of  the  bowel  causes  diar- 
rhea and  consequent  weakness. 

TRYPANOSOMIASIS   (SLEEPING-SICKNESS) 

Definition. — A  chronic  disorder  due  to  the  Trypano- 
soma  gambiense,  characterized  by  fever,  lassitude, 
weakness,  and  often  protracted  lethargy. 

Etiology. — This  disease  is  prevalent  in  West  Africa 
and  is  due  to  the  trypanosome.  Infection  occurs  by 
the  bite  of  a  fly,  the  Glossina  palpalis.  This  fly  lives 
on  the  bushes  and  weeds  along  the  shores  of  streams 
and  lakes. 

Morbid  Anatomy. — The  parasite  is  found  in  the  cere- 
brospinal  fluid  and  blood.  In  the  early  stage  of  the  dis- 
ease the  lymphatic  glands  are  enlarged  and  the  parasite 
is  found  in  them. 

Morbid  Physiology. — The  manner  in  which  the 
parasite  produces  its  characteristic  disturbances — 
fever,  rapid  pulse,  dulling  of  the  mind,  tremors,  and, 
finally,  subnormal  temperature  and  coma — has  not  yet 
been  determined. 

MALARIAL   FEVER  (AGUE) 

Definition. — An  infectious  disease  caused  by  the 
Plasmodium  malariae,  characterized  by  periodic  occur- 
rences of  chill,  fever,  and  sweating. 

Etiology. — The  disease  is  contracted  through  the  bite 


192  PATHOLOGY 

of  the  Anopheles  mosquito,  in  whose  body  the  parasite 
passes  through  its  sexual  cycle  of  development.  In 
the  red  blood-corpuscles  of  the  warm-blooded  host  an 
asexual  cycle  of  development  takes  place,  each  parasite 
developing  into  fifteen  to  twenty  spores  or  daughter- 
cells,  the  chills  and  fever  characteristic  of  the  disease 
being  coincident  with  the  maturing  and  scattering  into 
the  blood  of  these  daughter-cells.  After  several  genera- 
tions, sexual  forms  are  developed,  which,  however,  are 
incapable  of  fertilization  in  the  blood.  When  the  blood 
enters  the  stomach  of  the  mosquito  the  male  elements 
fertilize  the  female  elements,  which  enter  the  walls  of  the 
stomach  and  give  birth  to  a  swarm  of  the  asexual  form 
of  the  parasite.  Numbers  of  these  gather  in  the  veneno- 
salivary  glands  and  are  injected  into  man  when  the 
mosquito  feeds  upon  him. 

Morbid  Anatomy. — The  morbid  alterations  are  the 
result  of  the  disintegration  of  the  red  blood-corpuscles, 
the  accumulation  of  pigment  thus  formed,  and  possibly 
to  the  development  of  a  toxin.  The  spleen  is  enlarged 
and  there  may  be  parenchymatous  degeneration  of  the 
kidneys.  The  liver  is  enlarged  and  turbid.  Anemia 
rapidly  develops,  with  a  lowering  of  the  hemoglobin. 

Morbid  Physiology. — The  chill,  fever,  and  sweating 
are  the  result  of  the  changes  in  the  blood,  which  takes 
place  with  the  maturing  of  the  parasites  within  the  red 
corpuscles,  which  are  rapidly  destroyed  thereby. 


DISEASES  DUE  TO  ANIMAL  PARASITES  193 

DISEASES  CAUSED  BY  CESTODES 
TAPEWORMS 

Tapeworms  have  two  states — the  larval  state,  which 
is  found  in  one  species  of  animal,  and  the  adult  state, 
occurring  in  another  species. 

Tsenia  Solium,  or  Pork  Tapeworm. — This  is  composed 
of  a  small  head  armed  with  suckers  and  a  double  row  of 
booklets,  whereby  it  attaches  itself  to  the  intestines,  a 
slender  neck,  and  numerous  segments  which  compose 
the  body.  Each  segment  contains  male  and  female 
elements.  At  maturity  the  segments  contain  thousands 
of  ripe  ova.  The  segments  are  continually  discharged 
with  the  bowel  movements.  Each  ovum  contains  an 
embryo  with  six  booklets.  To  develop  further,  the 
ovum  must  be  taken  into  the  stomach  of  the  pig  or  man. 
There  the  shell  is  digested,  and  the  embryo  set  free, 
passes  through  the  stomach  wall  and  becomes  encysted 
in  various  organs,  as  the  muscles,  brain,  liver,  or  eye, 
where  they  develop  into  larvae  or  cysticerci.  When  the 
flesh  containing  the  cysticerci  is  eaten  by  man  or  cer- 
tain other  animals  the  cyst  is  dissolved,  the  parasite 
fastens  itself  to  the  mucous  membrane  of  the  intestine, 
and  develops  into  the  adult  worm,  with  segments  and 
ova  as  before.  While  either  the  larval  or  the  adult 
stage  of  this  tapeworm  may  occur  in  man,  it  is  usually 
the  adult  type  to  whom  man  is  host. 

Morbid  Anatomy. — No  anatomic  changes  occur. 

Morbid  Physiology. — Practically  the  only  disturbance 

13 


194  PATHOLOGY 

caused  by  this  parasite  is  due  to  local  irritation — 
diarrhea,  pain,  and  nausea.  Occasionally  chorea  and 
convulsions  occur.  It  has  been  thought  that  products 
of  this  parasite  have  a  hemolytic  action,  thus  causing 
the  anemia. 

T«nia  Saginata. — This  worm  passes  the  larval  state 
in  cattle  and  the  adult  state  only  in  man.  It  differs 
only  in  size  and  shape  from  the  solium,  and  the  dis- 
turbances caused  are  the  same. 

Cysticercus  Cellulosae. — When  the  ripe  ova  of  Taenia 
solium  are  accidentally  swallowed  by  man  he  becomes 
the  host  for  the  larval  form  of  the  parasite,  a  much  more 
serious  matter  than  harboring  the  adult  parasite.  The 
results  depend  upon  the  number  of  the  ova  swallowed 
and  upon  the  organs  upon  which  they  locate.  In  the 
muscles  they  cause  soreness  and  pain;  in  the  eye,  pos- 
sibly blindness;  in  the  brain,  various  undefined  nervous 
manifestations,  all  due  to  the  irritation  and  pressure  of 
their  growth. 

ECHINOCOCCUS  DISEASE 

This  parasite  occurs  in  the  larval  state  in  man,  the 
adult  stage  being  passed  in  the  dog,  wolf,  and  fox. 
The  eggs  having  been  swallowed,  the  embryo  parasite  is 
freed  in  the  stomach,  penetrates  the  mucous  membrane, 
and  is  carried  by  the  blood  to  the  liver,  spleen,  kidneys, 
or  brain,  where  it  develops  an  echinococcus  cyst,  a 
sac  containing  fluid  and  the  parasite.  The  cyst  may 


DISEASES  DUE  TO  ANIMAL  PARASITES  195 

reach  enormous  size,  or  the  parasite  may  die  and  the 
cyst  shrivel  and  disappear. 

Morbid  Anatomy. — The  increasing  size  of  the  cyst 
causes  destruction  of  surrounding  tissue  and  pressure- 
atrophy.  In  the  brain,  death  may  occur  early  with 
pressure  symptoms. 

Morbid  Physiology. — This  depends  upon  the  location 
of  the  cyst  and  its  size. 

DISEASES  CAUSED  BY  NEMATODES  OR  ROUND-WORMS 

ASCARIS  LUMBRICOIDES 

This  is  one  of  the  most  common  small  parasites  affect- 
ing man.  The  worm  develops  in  the  small  intestine 
after  swallowing  of  the  eggs  in  food  or  drink.  The 
worm  resembles  in  appearance  the  earthworm  or  common 
angleworm.  While  it  inhabits  the  small  intestine  prin- 
cipally, it  sometimes  migrates  to  other  parts,  as  the 
gall-ducts,  the  stomach,  the  esophagus,  or  even  the 
larynx.  They  give  rise  to  few  symptoms  aside  from 
intestinal  irritation.  Large  masses  have  caused  intesti- 
nal obstruction. 

OXYURIS  VERMICULARIS 

This  parasite  is  termed  the  thread-worm  or  seat- worm. 
It  inhabits  the  colon  or  rectum  commonly  in  children. 
It  may  migrate  to  the  vagina.  It  causes  intense  itching 
and  irritation. 


196  PATHOLOGY 

TRICHINA  SPIRALIS 

Trichina  occurs  in  both  the  larval  and  adult  form  in 
man  and  the  lower  animals.  Infection  occurs  from  eat- 
ing improperly  cooked  pork.  The  larvae  are  set  free, 
develop  into  adults  in  the  intestines,  where  they  dis- 
charge embryos.  Some  of  the  embryos  die  or  escape 
by  the  feces,  while  others  penetrate  the  intestinal  wall, 
and  are  either  carried  by  the  blood  or  lymph-stream  or 
by  their  own  migrations  to  the  muscles,  where  they  be- 
come encysted.  When  the  migration  begins,  symptoms 
of  intestinal  irritation,  with  fever,  vomiting,  and  perhaps 
collapse  occur,  followed  by  excruciating  pain  in  the 
muscles  resembling  rheumatism,  the  gravity  of  the 
disturbance  depending  upon  the  number  of  the  parasites 
developed. 

ANKYLOSTOMA  DUODENALE   (HOOK-WORM) 

This  worm  is  so  called  from  the  head  being  armed 
with  six  sharp  hook-like  teeth,  whereby  it  fastens 
itself  to  the  wall  of  the  small  intestine.  The  parasite 
causes  intense  anemia  and  debility.  It  is  thought 
that  a  poison  is  secreted  by  the  worm,  which  causes 
the  profound  blood  changes. 

FILARIA  SANGUINIS  HOMINIS 

This  is  a  small  worm  about  the  thickness  of  the  diam- 
eter of  a  red  blood-corpuscle.  Infection  occurs  through 
the  bite  of  a  mosquito,  in  whose  body  occurs  one  cycle 


DISEASES  DUE  TO  ANIMAL  PARASITES  197 

in  its  life-history.  It  is  a  disease  of  tropical  climates. 
The  embryos  may  be  found  in  considerable  numbers  in 
the  blood  at  night  in  day  workers,  or  during  the  day  in 
those  who  work  during  the  night.  The  embryos  occur 
in  such  numbers  at  times  as  to  block  the  lymph-channels, 
producing  the  conditions  known  as  hematochyluria,  ele- 
phantiasis, and  lymphy  scrotum. 

Morbid  Anatomy. — Opportunities  for  examining  these 
cases  postmortem  are  rare.  In  a  case  examined,  the 
renal  and  peritoneal  lymph-plexuses  were  enormously 
distended. 

Morbid  Physiology. — Chyle  and  blood  are  passed 
with  the  urine,  and  the  scrotum  becomes  infiltrated 
with  lymph,  which  flows  freely  if  the  skin  be  punctured. 


INDEX 


ABSCESS,  144,  157 
Acetic  acid  fermentation,  22 
Acetozone,  64 
Acids,  production  of,  21 
Actinomyces,  177 
Actinomycosis,  177 
Adenocarcinoma,  154 
Adenoma,  152 
Adenosarcoma,  152 
Aerobic  bacteria,  21 
Agglutination,  26 
Agglutinins,  26 
Aggressins,  26 
Ague,  191 
Air,  34 

insufficient,  128 
Alcohol,  65 
Alexins,  82 

Amebic  dysentery,  190 
Amoeba  dysenteriae,  58,  190 
Anaerobic  bacteria,  21 
Anaphylaxis,  123 
Anemia,  local,  135 
Anemic  infarct,  137 
Angioma,  150 
Animal  parasites,  diseases  due  to, 

190 

Ankylostoma  duodenale,  196 
Anopheles  mosquito,  192 
Anthrax,  176 

bacillus  of,  52 

immunity  to,  86 
Antibodies,  82 


Antimeningitis  serum,  97 
Antiseptics,  60 
Antitoxin,  27,  89 

diphtheria,  91 

plague,  99 

preparation  of,  91 

tetanus,  95 

typhoid,  99 
Aristol,  66 

Ascaris  lumbricoides,  195 
Ascites,  138 
Asiatic  cholera,  166 
Asphyxia,  128 
Atrophy,  139 
Autogenous  vaccines,  103 

BACILLI,  16,  44 
Bacillus  anthracis,  52 

diphtherias,  46 

Eberth,  48 

influenzas,  52 

Klebs-Loffler,  46 

lactis,  21 

leprae,  54 

mallei,  53 

of  bubonic  plague,  54 

of  tetanus,  51 

pyocyaneus,  38 

tuberculosis,  44 

typhosus,  48 
Bacteria,  classification  of,  16 

composition  of,  16 

definition  of,  16 


200 


INDEX 


Bacteria,  diseases  due  to,  156 

discovery  of,  12 

embolism  caused  by,  136 

examination  of,  29 

in  soil,  19,  36 

local  effects  of,  156 

methods  of  reproduction,  16 
of  studying,  29 

motile,  1 6 

products  of,  21 

spores  of,  17 

staining  of,  29 
Bacterial  vaccines,  27,  103 
Bacteriology,  16 

history  of,  n 

introduction  to,  n 
Bacteriolysis,  25 
Behring,  15 

Bismuth  subnitrate,  67 
Blood-poisoning,  38 
Bubonic  plague,  171 
bacillus  of,  54 
vaccine,  104 
Butyric  acid  fermentation,  22 

CALMETTE'S  reaction,  46,  117 
Cancer,  152 
Carbolic  acid,  62 
Carcinoma,  152 

nature  of,  152,  153 

pathology  of,  153 

structure"of,  153 

varieties  of,  154 
Caseation,  140,  169 
Cats  carriers  of  disease,  35 
Caustic  poisons,  128 
Cellulitis,  144 
Cerebrospinal  fever,  162 
Cestodes,  193 
Chancre,  180 
Cholera,  166 

spirilla,  56 


Cholera  vaccine,  56,  113 

Chondroma,  149 

Cicatrix,  144 

Circulation,  disturbances  of,  134 

Cloudy  swelling,  139 

Coccus,  1 6 

Complement,  deviation  of,  120 

Congestion,  hypostatic,  134 

Contagious  diseases,  33 

Corrosive  poisons,  128 

sublimate,  61 

Credo's  method  in  newborn,  62 
Cutaneous  tuberculin  test,  116 
Cysticerci  of  tapeworm,  194 
Cysts,  dermoid,  155 

echinococcus,  194 

DAUGHTER-CELLS,  malarial,  23 
Davaine,  14 
Degeneration,  139,  143 
Deodorants,  60 
Dermoid  cyst,  155 
Deviation  of  complement,  120 
Diabetes,  131 
Diapedesis,  135 
Diphtheria,  160 

antitoxin,  91 

bacillus  of,  46 

carrier,  161 

membrane  of,  161 

precautions  in,  161 

toxin,  91 
Diplococcus  intracellularis,  42 

meningitidis,  42 

pneumoniae,  41 
Diseases  due  to  animal   parasites 

100 

to  bacteria,  156 
to  protozoa,  190 

whose  causes  have  not  been  iso- 
lated  184 
Disinfectants,  60 


INDEX 


2OI 


Disinfection,  75 

Disorders  of  metabolism  and  nutri- 
tion, 130 

Disturbances  of  circulation,  134 
Dogs,  35 
Dropsy,  138 
Dust,  34 
Dysentery,  190 

EBERTH'S  bacillus,  48 
Ecchymosis,  135 
Echinococcus  cyst,  194 
Ectogenous  teratoma,  155 
Edema,  138 

definition  of,  138 

inflammatory,  138 

of  abdominal  cavity,  138 

of  thoracic  cavity,  138 
Elephantiasis,  196 
Emboli,  kinds  of,  136 
Embolism,  definition  of,  136 

results  of,  136 
Embryonic  rests,  147 
Emigration  of  leukocytes,  135 
Endogenous  teratoma,  155 
Enterorrhagia,  136 
Epidemic  cerebrospinal  meningitis, 

162 

Epistaxis,  136 
Epithelioma,  152 
Erysipelas,  157 
Etiology  of  disease,  126 
Exostosis,  149 
Exposure  to  high  temperature,  127 

to  low  temperature,  127 
External  defenses  of  organism,  70 

FACULTATIVE  aerobes,  21 

anaerobes,  21 
Farcy,  175 
Fat  embolism,  136 
Fatty  degeneration,  139 


Fever,  132 

definition  of,  132 

etiology  of,  132 

nature  of,  133 
Fibroma,  148 

Filaria  sanguinis  hominis,  196 
Flagella,  16 
Fleas,  35,  172 
Flies,  35,  75,  76,  78,  79 
Food  as  source  of  infection,  35 

definition  of,  130 

increased  supply  of,  130 

insufficient  supply  of,  130 

of  bacteria,  21 
Formalin,  63 
Formidin,  66 
Frankel's  pneumococcus,  41 

GANGRENE,  141 

black,  141 

dry,  141 

moist,  141 

white,  141 
Germicides,  60 

Giant  cells  of  tuberculosis,  16 
Giant-celled  sarcoma,  152 
Gibraltar  fever,  183 
Glanders,  175 

bacillus  of,  53 
Glioma,  150 
Globulins,  93 
Gonococcus  of  Neisser^  43 

vaccine,  104 
Gonorrhea,  158 
Gout,  131 

Gray  hepatization,  160 
Gruber-Widal  reaction,  118 
Gummata,  180 

HAFFKINE'S  cholera  vaccine,  113 

Hanging  drop,  30 

Healing  by  first  intention,  145 


202 


INDEX 


Healing  by  granulation,  145 

by  second  intention,  145 
Heat  in  etiology  of  disease,  1 26 
Hemangioma,  150 
Hemolysis,  120 
Hemophilia,  136 
Hemoptysis,  136 
Hemorrhage,  135 

causes  of,  135,  136 

classification  of,  136 
Hepatization  of  lung,  159 
gray,  160 
red,  159 
Hookworm,  196 
Hydrogen  peroxid,  65 
Hydrophobia,  184 
Hydrothorax,  138 
Hyperemia,  134,  142 

active,  134 

arterial,  134 

local,  134 

passive,  134 

venous,  134 
Hyperplasia,  139,  146 
Hypertrophy,  145 

definition  of,  145 

numeric,  145 

simple,  146 
Hypostatic  congestion,  134 

IMMUNITY,  24,  80 

absolute,  81 

acquired,  26,  8 1 

inherited,  85 

mechanism  of,  80 

methods  of  producing,  85 

natural,  25 

theories  of,  28,  80 
Inanition,  130 
Infarct,  137 

anemic,  137 

hemorrhagic,  137 


Infarct,  red,  137 

white,  137 
Infection,  24 

avenues  of,  33 

mechanism  of,  68 

mixed,  39 

prevention  of,  73 

sources  of,  34 

susceptibility  to,  24 

transmission  of,  72 
Infectious  diseases,  33,  39 
Inflammation  and  processes  of  re- 
pair, 142 

changes  in  blood-vessels  in,  142 

definition  of,  142 

etiology  of,  142 

exudation  in,  143 

symptoms  of,  142 
Influenza,  178 

bacillus  of,  52 

Inoculation  with  dead  germs,  86 
living  germs,  85,  86 
toxins,  86 

lodid  of  mercury,  62 
lodin,  63 
lodoform,  66 
Ischemia,  135 

JENNER,  25 

KLEBS-LOFFLER  bacillus,  46 
Koch,  44 

Koch's  discovery  of  tubercle  bacil- 
lus, 15 

rules,  32 

tuberculin,  107 
Kolle's  vaccination  for  cholera,  114 

LACTIC  acid  bacillus,  21 
Laveran's  malarial  parasite,  58 
Leeuwenhoek's  discovery  of  bac- 
teria, 12 


INDEX 


203 


Leiomyoma,  150 
Leprolin,  54 
Leprosy,  170 

anesthetic,  171 

bacillus  of,  54 

tubercular,  170 

Leukocytes,  emigration  of,  135 
Light,  21 
Lipoma,  149 

Liquefaction  necrosis,  140 
Lobar  pneumonia,  158 
Local  anemia,  135 

hyperemia,  134 
Lymphadenoma,  151 
Lymphangioma,  150 
Lymphosarcoma,  151 
Lysol,  62 

MALARIA,  191 
Malarial  parasite,  58 
Malignant  pustule,  176 

tumors,  148 
Mallein,  53 
Malta  fever,  183 

micrococcus  of,  42 
Marketing  antitoxin,  94 
Mastoiditis,  157 
Measles,  186 
Melanosarcoma,  152 
Meningitis,  cerebrospinal,  42 

serum  treatment  of,  42 
Meningococcus,  42 
Mercury,  bichlorid  of,  61 

iodid  of,  62 

Metabolism,  disorders  of,  130 
Metchnikoff,  26 
Microbes,  16 
Micrococcus  gonorrheae,  43 

intracellularis,  42 

lanceolatis,  41 

melitensis,  42 

meningitidis,  42 


Micro-organisms,  16 
Microscopic  examination,  29 
Milk  as  source  of  infection,  34,  44 

in  tuberculosis,  44 
Mixed  infection,  39 
Moist  gangrene,  141 
Moisture,  20 

Moro  reaction  in  tuberculosis,  117 
Morphology  of  bacteria,  16 
Motility,  16 
Mucous  patches,  180 
Myoma,  150 
Myxoma,  145 

NATURAL  immunity,  25 
Necrosis,  140 

coagulation,  140 

definition  of,  140 

etiology  of,  140 

liquefaction,  140 
Negri  bodies,  185 
Neisser,  gonococcus  of,  43 
Nematodes,  195 
Neuroma,  150 
Nitrate  of  silver,  62 
Non-pathogenic  bacteria,  20 
Nurses,  precautions  for,  73 
Nutrition,  disorders  of,  130 

OBESITY,  130 
Oil-immersion  lens,  30 
Ophthalmo-tuberculin  reaction,  117 
Ophthalmotyphoid   tuberculin   re- 
action, 119 
Opsonic  index,  101 
Opsonins,  26,  101 
Osteoma,  149 
Osteomyelitis,  157 
Osteosarcoma,  152 
Otitis  media,  157 
Overfeeding,  130 


204 


INDEX 


Oxygen,  21 

Oxyuris  vermicularis,  195 

PARASITES,  animal  diseases  caused 
by,  190 

vegetable    diseases    caused    by, 

156 

Parasitic  bacteria,  19 
Parotitis,  188 
Passive  hyperemia,  134 

immunity,  81 
Pasteur,  14,  15 
Pathogenic  bacteria,  19,  41 
Pathology,  126 
Period  of  incubation,  34 
Pertussis,  188 
Phagocytes,  26 
Phagocytosis,  26 
Plague,  171 

bacillus  of,  54 

rat  flea  and,  172 

vaccine,  100 
Plasmodium  malariae,  58 
estivo-autumnal,  58 
quartan,  58 
tertian,  58 
Pneumococcus,  41 
Pneumonia,  158 
Poisons,  22,  128 

action  of  bacterial,  128 

corrosive,  128 

effects  of,  128 

immunity  to,  128 

organic,  128 

Poliomyelitis,  precautions  in,  79 
Potassium  permanganate,  63 
Precautions  for  nurses,  73 
Prevention  of  infection,  73 
Progressive  processes,  145 
Proliferation,  143 
Protozoa,  23,  58 
Ptomains,  22 


Puerperal  infection,  Oliver  Wendell 

Holmes  on,  12 
Purulent  infiltration,  144 
Pus,  144 

Pustule,  malignant,  176 
Putrefaction,  22 
Pyemia,  38 
Pyogenic  bacteria,  37 

membrane,  144 

QUARTAN  malaria,  58 

RABIES,  184 

vaccine,  in 
Ray  fungus,  177 
Regeneration,  145 
Relapsing  fever,  181 

spirillum  of,  47 
Repair  of  wounds,  145 
Reproduction,  bacterial,  17 
Resolution,  143 
Retrograde  processes,  139 
Rhabdomyoma,  150 
Round-cell  infiltration,  143 

sarcoma,  152 
Round-worms,  195 

SAPREMIA,  38 
Saprophytes,  19 
Sarcoma,  151 

classification  of,  152 
Scar,  144 
Scarlatina,  185 
Scarlet  fever,  187 
Sclerosis  of  lung,  169 
Semmelweis,  13 
Septicemia,  38 
Septic  infection,  38 
Serpents'  venom,  129 
Serum,  antimeningitis,  97 

antidiphtheritic,  91 

antitetanic,  95 


INDEX 


205 


Serum  diagnosis,  115 

reaction  of  Widal,  118 

testing,  93 

therapy,  88 
Silver  nitrate,  62 
Sinus,  145 

Sleeping-sickness,  191 
Small-pox,  78 

vaccine,  108 
Soil,  19,  36 
Spirillum  of  Asiatic  cholera,  55 

of  relapsing  fever,  57 
Spirochaeta  obermeieri,  57 

pallida,  56 
Spores,  17 
Sporulation,  17 
Staining  of  bacteria,  20,  30 
Standardization  of  antitoxin,  93 
Staphylococci,  37 
Staphylococcus,  37 

albus,  37 

aureus,  37 

cereus  albus,  38 

citreus,  38 

vaccine,  103 
Starvation,  130 
Steam,  62 
Sterilization,  61 
Stock  vaccines,  103 
Streptococcus  pyogenes,  38 

vaccine,  104 
Suffocation,  128 
Suppuration,  144 
Suppurative  diseases,  157 
Susceptibility,  68 

and  infection,  68 
Syphilis,  179 

acquired,  179 

Colics'  law  in,  179 

congenital,  179 

germ  of,  56,  179 

gummata  of,  180 


Syphilis,  primary  lesion  of,  180 
secondary  lesions  of,  180 
tertiary  lesions  of,  180 
Wassermann  test  for,  120 

TJENIA  echinococcus,  194 

saginata,  194 

solium,  193 
Tapeworm,  193 
Teratoma,  155 

bigeminal  155 

ectogenous,  155 

endogenous,  155 
Tertian  malaria,  58 
Test,  tuberculin,  115 

Wassermann,  120 

Widal,  118 
Testing  serum,  93 
Tetanus,  173 

antitoxin,  51 

bacillus  of,  51 

Therapeutic  action  of  antitoxin,  90 
Thrombosis,  137 

results  of,  137 
Toxin  of  diphtheria,  91 

of  tetanus,  93 
Toxins,  22 

Transmission  of  infection,  72 
Traumatism  as  cause  of   disease, 

126 

Treponema  pallidum,  56 
Trichina  spiralis,  196 
Trichiniasis,  196 
Trypanosomata,  59 

gambiensis,  191 
Trypanosomiasis,  191 
Tsetse  fly,  59 
Tuberculin,  106 

Koch's,  107 

new,  107 

O.  T.,  107 

reaction,  115 


206 


INDEX 


Tuberculin  T.  R.,  107 
test,  115 
treatment,  106 
Tuberculosis,  167 

bacillus  of,  44 
Tumors,  147 
benign,  148 
causes  of,  147 
classification  of,  148 
definition  of  (Hektoen),  147 
malignant,  148 
structure  of,  148 
Turpentine,  65 
Typhoid  fever,  164 
bacillus  of,  48 
ophthalmo-reaction,  50 
precautions  in,  75 
prevention  of  infection  in,  50 
transmission  of,  49 
vaccine,  105 
Widal  test  in,  49 
Typhus  fever,  189 

ULCER,  144 

VACCINATION,  25 
Vaccine,  bubonic  plague,  104 
cholera,  56,  113 


Vaccine,  gonococcus,  104 

rabies,  in 

small-pox,  25,  108 

staphylococcus,  103 

streptococcus,  104 

therapy,  100 

typhoid,  105 
Vaccines,  27,  103 

autogenous,  103 

bacterial,  27,  103 

stock,  103 
Vascular  nevi,  150 
Venom  of  insects,  129 

of  serpents,  1 29 

Virchow's  theory  of  tumors,  147 
Von  Pirquet's  test,  116 

WASSERMANN  test,  120 
Water  as  carrier  of  infection,  34 
White  infarct,  137 
Whooping-cough,  188 
Widal  reaction,  118 
Wolff-Eisner  test,  117 
Wool-sorters'  disease,  176 
Wound  repair,  145 
Wright  and  Douglas,  26 

YELLOW  fever,  185 


Books  for  Nurses 


PUBLISHED   SY 

W.    B.   SAUNDERS   COMPANY 

West  Washington  Square  Philadelphia 

London:    9,  Henrietta  Street,  Covent  Garden 

Sanders'   N ursing  A  NEW  WORK 

Miss  Sanders'  new  book  is  undoubtedly  the  most 
complete  and  most  practical  work  on  nursing  ever 
published.  Every  thing  about  every  subject  with 
which  the  nurse  should  be  familiar  is  detailed  in 
a  clean  cut,  definite  way.  There  is  no  other 
nursing  book  so  full  of  good,  practical  informa- 
tion— information  you  need. 

Modern  Methods  in  Nursing.  By  GEORGIANA  J.  SANDERS, 
formerly  Superintendent  of  Nurses  at  Massachusetts  Gen- 
eral Hospital.  121110  of  881  pages,  with  227  illustrations. 

Cloth,  $2.50  net. 

Aikens'  Home  Nurse's  Handbook 

PRACTICAL 

The  point  about  this  work  is  this:  It  tells  you, 
and  shows  you  just  how  to  do  those  little — but 
none  the  less  important — things  entirely  omitted 
from  other  nursing  books,  or  at  best  only  inci- 
dentally treated.  The  chapters  on  "Home  Treat- 
ments" and  "Every-Day  Care  of  the  Baby," 
stand  out  as  particularly  practical.  Then  the 
"  Points  to  be  Remembered" — terse,  crisp  re- 
minders— is  a  feature  of  great  value. 

Home  Nurse's  Handbook.  By  CHARLOTTE  A.  AIKENS, 
formerly  Director  of  the  Sibley  Memorial  Hospital,  Wash- 
ington, D.C.  i2mo  of  276  pages,  illustrated.  Cloth,  $1.50  nei 


Stoney's  Nursing 


NEW   (4th)  EDITION 


Of  this  work  the  American  Journal  of  Nursing  says:  "It  is  the 
fullest  and  most  complete  and  may  well  be  recommended  as 
being  of  great  general  usefulness.  The  best  chapter  is  the  one 
on  observation  of  symptoms  which  is  very  thorough."  There 
are  directions  how  to  improvise  everything. 

Practical  Points  in  Nursing.  By  EMILY  M.  A.  STONEY,  formerly  Super- 
intendent of  the  Training  School  for  Nurses  in  the  Carney  Hospital, 
South  Boston,  Mass,  izmo,  495  pages,  illustrated.  Cloth,  $1.75  net. 


NEW    (3d)    EDITION 


Stoney's  Materia  Medica 

Stoney's  Materia  Medica  was  written  by  a  head  nurse  who 
knows  just  what  the  nurse  needs.  American  Medicine  says 
it  contains  "all  the  information  in  regards  to  drugs  that  a 
nurse  should  possess." 

Materia  Medica  for  Nurses.  By  EMILY  M.  A.  STONEY,  formerly  Super- 
intendent of  the  Training  School  for  Nurses  in  the  Carney  Hospital, 
South  Boston,  Mass.  12010  volume  of  300  pages.  Cloth,  $1.50  net. 


Stoney's  Surgical  Technic      NEw  (3d>  EDITION 

The  first  part  of  the  book  is  dovoted  to  Bacteriology  and 
Antiseptics;  the  second  part  to  Surgical  Technic,  Signs  of 
Death,  Bandaging,  Care  of  Infants,  etc. 

Bacteriology  and  Surgical  Technic  for  Nurses.  By  EMILY  M.  A. 
STONEY.  Revised  by  FREDERIC  R.  GRIFFITH,  M.  D.,  New  York. 
i2mo  volume  of  311  pages,  fully  illustrated.  Cloth,  $1.50  net. 

Goodnow's  First- Year  Nursing  ILLUSTRATED 

Miss  Goodnow's  work  deals  entirely  with  the  practical  side  of 
first-year  nursing  work.  It  is  the  application  of  text-book 
knowledge.  It  tells  the  nurse  how  to  do  those  things  she  is  called 
upon  to  do  in  her  first  year  in  the  training  school — the  actual 
ward  work. 

First-Year  Nursing.  By  MINNIE  GOODNOW,  R.  N.,  formerly  Super- 
intendent of  the  Women's  Hospital.  Denver.  lamoof  328  pages, 
illustrated.  Cloth,  $1.50  net. 


Aikens'  Hospital  Management 

This  is  just  the  work  for  hospital  superintendents,  training- 
school  principals,  physicians,  and  all  who  are  actively  inter- 
ested in  hospital  administration.  The  Medical  Record  says: 
"Tells  in  concise  form  exactly  what  a  hospital  should  do 
and  how  it  should  be  run,  from  the  scrubwoman  up  to  its 
financing." 

Hospital  Management.  Arranged  and  edited  by  CHARLOTTE  A. 
AIKENS,  formerly  Director  o"  Sibley  Memorial  Hospital,  Washing- 
ton, D.  C.  i2mo  of  488  pages,  illustrated.  Cloth,  $3.00  net 

Aikens'  Primary  Studies         NEW  ^  EDITION 

Trained  Nurse  and  Hospital  Review  says:  "It  is  safe  to  say 
that  any  pupil  who  has  mastered  even  the  major  portion  of 
this  work  would  be  one  of  the  best  prepared  first  year  pupils 
who  ever  stood  for  examination." 

Primary  Studies  for  Nurses.  By  CHARLOTTE  A.  AIKENS,  formerly 
Director  of  Sibley  Memorial  Hospital,  Washington,  D.  C.  i2mo  of 
437  pages,  illustrated.  Cloth,  $1.75  net. 

Aikens'  Training-School  Methods  and 
the  Head  Nurse 

This  work  not  only  tells  how  to  teach,  but  also  what  should 
be  taught  the  nurse  and  how  much.  The  Medical  Record  says: 
"  This  book  is  original,  breezy  and  healthy." 


Hospital  Training-School  Methods  and  the  Head  Nurse.      By 
LOTTE  A.  AIKENS,  formerly   Director   of  Sibley  Memorial  Hospital, 
Washington,  D.  C.    12010  of  267  pages.  Cloth,  $1.50  net 

Aikens'    Clinical    Studies       NEW  (2d)  EDITION 

This  work  for  second  and  third  year  students  is  written  on  the 
same  lines  as  the  author's  successful  work  for  primary  stu- 
dents. Dietetic  and  Hygienic  Gazette  says  there  '  '  is  a  large 
amount  of  practical  information  in  this  book." 

Clinical  Studies  for  Nurses.  By  CHARLOTTE  A.  AIKENS,  formerly 
Director  of  Sibley  Memorial  Hospital,  Washington,  D.  C.  12010  of 
569  pages,  illustrated  Cloth,  $2.00  net 


Bolduan  and  Grund's  Bacteriology 

The  authors  have  laid  particular  emphasis  on  the  immediate 
application  of  bacteriology  to  the  art  of  nursing.  It  is  an 
applied  bacteriology  in  the  truest  sense.  A  study  of  all  the 
ordinary  modes  of  transmission  of  infection  are  included. 

Applied  Bacteriology  for  Nurses.  By  CHARLES  F.  BOLDUAN,  M. D., 
Assistant  to  the  General  Medical  Officer,  and  MARIE  GRUND.  M.D., 
Bacteriologist,  Research  Laboratory,  Department  of  Health,  City  of 
New  York,  izmo  of  166  pages,  illustrated.  Cloth,  $1.25  net. 

Fiske's  The  Body  ANEW  IDEA 

Trained  Nurse  and  Hospital  Review  says  "it  is  concise,  well- 
written  and  well  illustrated,  and  should  meet  with  favor  in 
schools  for  nurses  and  with  the  graduate  nurse." 

Structure  and  Functions  of  the  Body.  By  ANNETTE  FlSKE,  A.  M.t 
Graduate  of  the  Waltham  Training  School  for  Nurses,  Massa- 
chusetts, izmo  of  221  pages,  illustrated.  Cloth,  $1.25  net 


Beck's  Reference  Handbook 


NEW  (3d)  EDITION 


This  book  contains  all  the  information  that  a  nurse  requires 
to  carry  out  any  directions  given  by  the  physician.  The 
Montreal  Medical  Journal  says  it  is  "  cleverly  systematized  and 
shows  close  observation  of  the  sickroom  and  hospital  regime." 

A  Reference  Handbook  for  Nurses.  By  AMANDA  K.  BECK.  Grad- 
uate of  the  Illinois  Training  School  for  Nurses,  Chicago.  III. 
3amo  volume  of  244  pages.  Bound  in  flexible  leather,  $x.a$  n«t 

Roberts'  Bacteriology  &  Pathology 

This  new  work  is  practical  in  the  strictest  sense.  Written 
specially  for  nurses,  it  confines  itself  to  information  that  the 
nurse  should  know.  All  unessential  matter  is  excluded.  The 
style  is  concise  and  to  the  point,  yet  clear  and  plain.  The  text 
is  illustrated  throughout. 

Bacteriology  and  Pathofogy  for  Nurses.  By  JAY  G.  ROBERTS,  Ph.  G., 
M.  D.,  Oskaloosa,  Iowa.  tamo  of  206  pages,  illustrated.  $1.25  net. 


DeLee's  Obstetrics  for  Nurses 

Dr.  Delyee's  book  really  considers  two  subjects — obstetrics 
for  nurses  and  actual  obstetric  nursing.  Trained  Nurse  and 
Hospital  Review  says  the  "book  abounds  with  practical 
suggestions,  and  they  are  given  with  such  clearness  that 
they  cannot  fail  to  leave  their  impress." 

Obstetrics  for  Nurses.     By  JOSEPH  B.  DELEE,  M.  D.,  Professor  of 

Obstetrics  at  the  Northwestern  University  Medical  School,  Chicago. 
i2mo  volume  of  508  pages,  fully  illustrated.  Cloth,  $2.50  net. 

Davis'  Obstetric  &  Gynecologic  Nursing 

NEW  (4th)  EDITION 

The  Trained  Nurse  and  Hospital  Review  says:  "  This  is  one 
of  the  most  practical  and  useful  books  ever  presented  to  the 
nursing  profession."  The  text  is  illustrated. 

Obstetric  and  Gynecologic  Nursing.  By  EDWARD  P.  DAVIS.  M.  D., 
Professor  of  Obstetrics  in  the  Jefferson  Medical  College,  Philadel- 
phia, i^mo  volume  of  480  pages,  illustrated.  Buckram,  $1.75  net. 

Macfarlane's  Gynecology  for  Nurses 

JUST  READY— NEW  (2d)  EDITION 

Dr.  A.  M.  Seabrook,  Woman's  Hospital  of  Philadelphia,  says: 
"It  is  a  most  admirable  little  book,  covering  in  a  concise  but 
attractive  way  the  subject  from  the  nurse's  standpoint.  You 
certainly  keep  up  to  date  in  all  these  matters,  and  are  to  be 
complimented  upon  your  progress  and  enterprise." 

A  Reference  Handbook  of  Gynecology  for  Nurses.  By  CATHARINE 
MACFARLANE,  M.  D.,  Gynecologist  to  the  Woman's  Hospital  of  Phil- 
adelphia. 32mo  of  156  pages,  with  70  illustrations.  Flexible  leather, 
$1.25  net. 


McKenzie's  Exercise  in  Education  and  Medicine 

Exercise  in  Education  and  Medicine.  By  R.  TAIT 
McK^NZiK,  B.A.,  M.D.,  Professor  of  Physical  Educa- 
tion, and  Director  of  the  Department,  University  of 
Pennsylvania.  Octavo  of  406  pages,  with  346  illustra- 
tions. Cloth,  $3.50  net. 


Bohm  &  Painter's  Massage 

The  methods  described  are  those  employed  in  Hoffa's  Clinic 
— methods  that  give  results.  Every  step  is  illustrated,  showing 
you  the  exact  direction  of  the  strokings.  The  pictures  are 
large. 

Octavo  of  QI  pages,  with  q?  illustrations.  By  MAX  BOHM,  M.  D., 
Berlin,  Germany.  Edited  by  CHARLES  F.  PAINTER,  M.  D.,  Professor 
of  Orthopedic  Surgery,  Tufts  College  Medical  School,  Boston. 

Cloth,  $1.75  net. 

Eye,  Ear,  Nose,  and  Throat  Nursing 

Medical  Record  says:  "Every  side  of  the  question  has  been 
fully  taken  into  consideration." 

Nursing  in  Diseases  of  the  Eye,  Ear.  Nose  and  Throat.  By  the 
Committee  on  Nurses  of  the  Manhattan  Eye,  Ear  and  Throat  Hospital. 
iamo  of  260  pages,  illustrated.  Cloth,  $1.50  net. 

Friedenwald  and  Ruhrah's  Dietetics  for 

IN  lirSCS  JUST  READY— NEW  (3d)  EDITION 

This  work  has  been  prepared  to  meet  the  needs  of  the  nurse, 
both  in  training  school  and  after  graduation.  American  Jour- 
nal of  Nursing  says  it  "is  exactly  the  book  for  which  nurses 
and  others  have  long  and  vainly  sought." 

Dietetics  for  Nurses.  By  JULIUS  FRIEDENWALD,  M.  D.,  Professor 
of  Diseases  of  the  Stomach,  and  JOHN  RUHRAH,  M.  D.,  Professor  of 
Diseases  of  Children,  College  of  Physicians  and  Surgeons,  Baltimore. 
i2mo  volume  of  431  pages.  Cloth,  $1.50  net 

Friedenwald  &  Ruhrah  on  Diet 

Diet  in  Health  and  Disease.       By  Juuus 
WAI,D,  M.D.,  and  JOHN  RUHRAH,  M.D.     Octavo  vol- 
ume of  857  pages.  Cloth,  $4.00  net. 

Galbraith's   Personal  Hygiene  and  Physical 

Training  for    Women  ILLUSTRATED 

Personal  Hygiene  and  Physical  Training  for  Women.  By  ANNA  M. 
GALBRAITH,  M.  D.,  Fellow  New  York  Academy  of  Medicine.  i2mo 
of  371  pages,  illustrated.  Cloth,  $2.00  net. 

Galbraith's  Four  Epochs  of  Woman's  Life 

THE  NEW  (2d)  EDITION 

The  Four  Epochs  of  Woman's  Life.  By  ANNA  M.  GALBRAITH.  M.D. 
With  an  Introductory  Note  by  JOHN  H.  MUSSBR,  M.  D..  University 
of  Pennsylvania,  nmo  of  247  pages.  .  Cloth.  $1.50  net 


McCombs'  Diseases  of  Children  for  Nurses 

NEW  (2d)   EDITION 

Dr.  McCombs'  experience  in  lecturing  to  nurses  has  enabled 
him  to  emphasize  just  those  points  that  nurses  most  need  to  know. 
National  Hospital  Record  says:  "We  have  needed  a  good 
book  on  children's  diseases  and  this  volume  admirably  fills 
the  want."  The  nurse's  side  has  been  written  by  head 
nurses,  very  valuable  being  the  work  of  Miss  Jennie  Manly. 

Diseases  of  Children  for  Nurses.  By  ROBERT  S.  McCOMBS,  M.  D.. 
Instructor  of  Nurses  at  the  Children's  Hospital  of  Philadelphia.  iamo 
of  470  pages,  illustrated.  Cloth,  $2.00  net 

Wilson's  Obstetric  Nursing  NEW  (2d>  EDITION 

In  Dr.  Wilson's  work  the  entire  subject  is  covered  from  the 
beginning  of  pregnancy,  its  course,  signs,  labor,  its  actual 
accomplishment,  the  puerperium  and  care  of  the  infant. 
American  Journal  of  Obstetrics  says:  "  Every  page  empasizes 
the  nurse's  relation  to  the  case." 

A  Reference  Handbook  of  Obstetric  Nursing.  By  W.  REYNOLDS 
WILSON,  M.D.,  Visiting  Physician  to  the  Philadelphia  Lying-in  Char- 
*1y.  32010  of  355  pages,  illustrated.  Flexible  leather,  $1.25  net 

American  Pocket  Dictionary  NEW 

The  Trained  Nurse  and  Hospital  Review  says:  "We  have 
had  many  occasions  to  refer  to  this  dictionary,  and  in  every 
instance  we  have  found  the  desired  information." 

American  Pocket  Medical  Dictionary.  Edited  by  W.  A.  NEWMAN 
DORLAND,  A.  M.,  M.  D.,  Loyola  University,  Chicago.  Flexible 
leather,  gold  edges,  $1.00  net;  with  patent  thumb  index,  $1.25  net 


THIRD 
EDITION 


Lewis'  Anatomy  and  Physiology 

Nurses  Joarnal  of  Pacific  Coast  says  * '  it  is  not  in  any  sense 
rudimentary,  but  comprehensive  in  its  treatment  of  the  sub- 
jects." The  low  price  makes  this  book  particularly  attractive. 

Anatomy  and  Physiology  for  Nurses.  By  LERov  LEWIS,  M.D.,  Lec- 
turer on  Anatomy  and  Physiology  for  Nurses,  Lewis  Hospital,  Bay 
City,  Mich.  i2mo  of  326  pages,  150  illustrations.  Cloth,  $1.75  net 


Boyd's  State  Registration  for  Nurses 

State  Registration  for  Nurses.  By  LOUIE  CROFT  BOYD,  R.  N.,  Grad- 
uate Colorado  Training  School  "for  Nurses.  Price,  50  cents  net. 

Paul's  Materia  Medica  NEW  (2d)  EDITION 

A  Text-Book  of  Materia  Medica  for  Nurses.  By  GEORGE  P.  PAUL,  M.D., 
Samaritan  Hospital,  Troy,  N.  Y.  ramo  of  282  pages.  Cloth,  $1.50  net. 

Paul's  Fever  Nursing  NEw  »«  ED,T,ON 

Nursing  in  the  Acute  Infectious  Fevers.  By  GEORGE  P.  PAUL,  M.D. 
i2mo  of  246  pages,  illustrated.  Cloth,  Si.oonet. 

Hoxie  &  Laptad's  Medicine  for  Nurses 

JUST  READY— NEW  (2d)  EDITION,  REWRITTEN 

Medicine  for  Nurses  and  Housemothers.  By  GEORGE  HOWARD 
HOXIE,  M.D.,  University  of  Kansas;  and  PEARL  L.  LAPTAD.  ismo 
of  351  pages,  illustrated.  .  Cloth,  $1.50  net. 


SECOND 
EDITION 


Grafstrom's  Mechano-therapy 

Mechano-therapy  (Massage  and  Medical  Gymnastics).  By  AXEL  V 
GRAFSTROM,  B.Sc.  M.D.,  i2mo,  200  pages.  Cloth,  $1.25  net. 

Nancrede's  Anatomy  NEW  a*)  EDITION 

Essentials  of  Anatomy.  CHARLES  B.  G.  DENANCREDE,  M.D.,  Univers- 
ity of  Michigan.  12010,  400  pages,  180  illustrations.  Cloth,  $1.00  net 

Morrow's  Immediate  Care  of  Injured 

Immediate  Care  of  the  Injured.  By  ALBERT  S.  MORROW,  M.D.,  New 
York  City  Home  for  Aged  and  Infirm.  Octavo  of  354  pages,  with 
242  Illustrations.  Clotr>.  $2.50  .net.  New  (2d)  Edition 

Register's  Fever  Nursing 


A  Text  Book  on  Practical  Fever  Nu'sing.  By  EDWARD  C.  REGISTER, 
M.D.,  North  Carolina  Medical  College.  Octavo  of  350  pages,  illus- 
trated. Cloth,  $2.50  net. 


Pyle's  Personal  Hygiene        NEW  (5th)  EDITION 

A  Manual  of  Personal  Hygiene.  Edited  by  WALTER  L.  PYLE,  M.D. 
Wills  Eye  Hospital.  Philadelphia.  i2mo,  |i|  pages,  illus.  $1.50  net. 

Morris'  Materia  Medica         NEW  (7.h)  EDITION 

Essentials  of  Materia  Medica,  Therapeutics,  and  Prescription  Writing. 
By  HENRY  MORRIS,  M.D.  Revised  by  W.  A.  BASTEDO,  M.D.,  Colum- 
bia University,  N.  Y.  12010  of  300  pages,  illustrated.  Cloth,  $1.00  net. 

Griffith's  Care  of  the  Baby     NEW^)  EDITION 

The  Care  of  the  Baby.  By  J.  P.  CROZER  GRIFFITH,  M.D.,  Univers- 
ity of  Pennsylvania.  12010  of  455  pages,  illustrated.  Cloth,  $1.50  net. 


DUE  AS  STAMPED  BELOW 


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